Firing circuit for surgical stapler

ABSTRACT

A surgical instrument includes a stapling head assembly, an anvil, a firing assembly, a motor, a user input feature, and an electrical circuit. The firing assembly actuates the stapling head assembly to drive an annular array of staples through tissue toward the anvil. The motor actuates the firing assembly through an actuation stroke to thereby actuate the stapling head assembly. The electrical circuit includes a trigger switch and an electrical latching feature. The trigger transitions from an open state to a closed state in response to the user input feature transitioning from a non-actuated state to an actuated state. The electrical circuit activates the motor in response to closure of the trigger switch. The electrical latching feature maintains activation of the motor to complete the actuation stroke even if the trigger switch is transitioned back to the open state before completion of the actuation stroke.

BACKGROUND

In some surgical procedures (e.g., colorectal, bariatric, thoracic,etc.), portions of a patient's digestive tract (e.g., thegastrointestinal tract and/or esophagus, etc.) may be cut and removed toeliminate undesirable tissue or for other reasons. Once the tissue isremoved, the remaining portions of the digestive tract may be coupledtogether in an end-to-end anastomosis. The end-to-end anastomosis mayprovide a substantially unobstructed flow path from one portion of thedigestive tract to the other portion of the digestive tract, withoutalso providing any kind of leaking at the site of the anastomosis.

One example of an instrument that may be used to provide an end-to-endanastomosis is a circular stapler. Some such staplers are operable toclamp down on layers of tissue, cut through the clamped layers oftissue, and drive staples through the clamped layers of tissue tosubstantially seal the layers of tissue together near the severed endsof the tissue layers, thereby joining the two severed ends of theanatomical lumen together. The circular stapler may be configured tosever the tissue and seal the tissue substantially simultaneously. Forinstance, the circular stapler may sever excess tissue that is interiorto an annular array of staples at an anastomosis, to provide asubstantially smooth transition between the anatomical lumen sectionsthat are joined at the anastomosis. Circular staplers may be used inopen procedures or in endoscopic procedures. In some instances, aportion of the circular stapler is inserted through a patient'snaturally occurring orifice.

Examples of circular staplers are described in U.S. Pat. No. 5,205,459,entitled “Surgical Anastomosis Stapling Instrument,” issued Apr. 27,1993; U.S. Pat. No. 5,271,544, entitled “Surgical Anastomosis StaplingInstrument,” issued Dec. 21, 1993; U.S. Pat. No. 5,275,322, entitled“Surgical Anastomosis Stapling Instrument,” issued Jan. 4, 1994; U.S.Pat. No. 5,285,945, entitled “Surgical Anastomosis Stapling Instrument,”issued Feb. 15, 1994; U.S. Pat. No. 5,292,053, entitled “SurgicalAnastomosis Stapling Instrument,” issued Mar. 8, 1994; U.S. Pat. No.5,333,773, entitled “Surgical Anastomosis Stapling Instrument,” issuedAug. 2, 1994; U.S. Pat. No. 5,350,104, entitled “Surgical AnastomosisStapling Instrument,” issued Sep. 27, 1994; and U.S. Pat. No. 5,533,661,entitled “Surgical Anastomosis Stapling Instrument,” issued Jul. 9,1996; and U.S. Pat. No. 8,910,847, entitled “Low Cost Anvil Assembly fora Circular Stapler,” issued Dec. 16, 2014. The disclosure of each of theabove-cited U.S. Patents is incorporated by reference herein.

Some circular staplers may include a motorized actuation mechanism.Examples of circular staplers with motorized actuation mechanisms aredescribed in U.S. Pub. No. 2015/0083772, entitled “Surgical Stapler withRotary Cam Drive and Return,” published Mar. 26, 2015; U.S. Pub. No.2015/0083773, entitled “Surgical Stapling Instrument with Drive AssemblyHaving Toggle Features,” published Mar. 26, 2015; U.S. Pub. No.2015/0083774, entitled “Control Features for Motorized Surgical StaplingInstrument,” published Mar. 26, 2015; and U.S. Pub. No. 2015/0083775,entitled “Surgical Stapler with Rotary Cam Drive,” published Mar. 26,2015. The disclosure of each of the above-cited U.S. Patent Publicationsis incorporated by reference herein.

While various kinds of surgical stapling instruments and associatedcomponents have been made and used, it is believed that no one prior tothe inventor(s) has made or used the invention described in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim this technology, it is believed this technologywill be better understood from the following description of certainexamples taken in conjunction with the accompanying drawings, in whichlike reference numerals identify the same elements and in which:

FIG. 1 depicts a perspective view of an exemplary circular stapler;

FIG. 2 depicts a perspective view of the circular stapler of FIG. 1,with a battery pack removed from a handle assembly and an anvil removedfrom a stapling head assembly;

FIG. 3 depicts a perspective view of the anvil of the circular staplerof FIG. 1;

FIG. 4 depicts another perspective view of the anvil of FIG. 3;

FIG. 5 depicts an exploded side elevational view of the anvil of FIG. 3;

FIG. 6 depicts a perspective view of the stapling head assembly of thecircular stapler of FIG. 1;

FIG. 7 depicts an exploded perspective view of the stapling headassembly of FIG. 6;

FIG. 8 depicts an exploded perspective view of the circular stapler ofFIG. 1, with portions of the shaft assembly shown separately from eachother;

FIG. 9 depicts a perspective view of the handle assembly of the circularstapler of FIG. 1, with a housing half omitted to reveal internalcomponents of the handle assembly;

FIG. 10 depicts a perspective view of a bracket of the handle assemblyof FIG. 9;

FIG. 11 depicts a perspective view of an indicator member of the handleassembly of FIG. 9;

FIG. 12A depicts a perspective view of an anvil actuation assembly ofthe circular stapler of FIG. 1, an actuation rod in a first position;

FIG. 12B depicts a perspective view of the anvil actuation assembly ofFIG. 12A, with the actuation rod moved to a second position to engagethe bracket of FIG. 10;

FIG. 12C depicts a perspective view of the anvil actuation assembly ofFIG. 12A, with the actuation rod moved to a third position to retractthe bracket of FIG. 10 proximally;

FIG. 12D depicts a perspective view of the anvil actuation assembly ofFIG. 12A, with a safety trigger pivoted from a first position to asecond position;

FIG. 12E depicts a perspective view of the anvil actuation assembly ofFIG. 12A, with a firing trigger pivoted from a first position to asecond position;

FIG. 13 depicts a perspective view of a stapling head actuation assemblyof the circular stapler of FIG.1;

FIG. 14 depicts a perspective view of a cam follower of the staplinghead actuation assembly of FIG. 13;

FIG. 15 depicts another perspective view of the cam follower of FIG. 14;

FIG. 16 depicts a perspective view of a rotary cam of the stapling headactuation assembly of FIG. 13;

FIG. 17 depicts another perspective view of the rotary cam of FIG. 16;

FIG. 18A depicts a side elevational view of the stapling head actuationassembly of FIG. 13, with the rotary cam in a first angular position andthe cam follower in a first pivotal position;

FIG. 18B depicts a side elevational view of the stapling head actuationassembly of FIG. 13, with the rotary cam in a second angular positionand the cam follower in a second pivotal position;

FIG. 19A depicts a perspective view of the rotary cam of FIG. 16, arocker member, and a stop switch, with the rotary cam in a first angularposition and the rocker member in a first pivotal position;

FIG. 19B depicts a perspective view of the rotary cam of FIG. 16, therocker member of FIG. 19A, and the stop switch of FIG. 19A, with therotary cam in a fourth angular position and the rocker member in asecond pivotal position;

FIG. 20A depicts a schematic end view of the rotary cam of FIG. 16, thecam follower of FIG. 14, and the rocker member of FIG. 19A, with therotary cam in the first angular position, the cam follower in the firstpivotal position, and the rocker member in the first pivotal position;

FIG. 20B depicts a schematic end view of the rotary cam of FIG. 16 andthe cam follower of FIG. 14, with the rotary cam in the second angularposition, the cam follower in the second pivotal position, and therocker member of FIG. 19A in the first pivotal position;

FIG. 20C depicts a schematic end view of the rotary cam of FIG. 16 andthe cam follower of FIG. 14, with the rotary cam in a third angularposition, the cam follower in the second pivotal position, and therocker member of FIG. 19A in the first pivotal position;

FIG. 20D depicts a schematic end view of the rotary cam of FIG. 16, thecam follower of FIG. 14, and the rocker member of FIG. 19A, with therotary cam in a fourth angular position, the cam follower in a thirdpivotal position, and the rocker member in a second pivotal position;

FIG. 21A depicts a cross-sectional side view of the anvil of FIG. 3positioned within a first section of a digestive tract and the staplinghead assembly of FIG. 6 positioned in a second section of the digestivetract, with the anvil separated from the stapling head assembly;

FIG. 21B depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 6 positioned in the second section of thedigestive tract, with the anvil secured to the stapling head assembly;

FIG. 21C depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 6 positioned in the second section of thedigestive tract, with the anvil retracted toward the stapling headassembly to thereby clamp tissue between the anvil and the stapling headassembly;

FIG. 21D depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 6 positioned in the second section of thedigestive tract, with the stapling head assembly actuated to sever andstaple the clamped tissue;

FIG. 21E depicts a cross-sectional side view of the first and secondsections of the digestive tract of FIG. 21A joined together at anend-to-end anastomosis;

FIGS. 22A-22B depict a flow chart showing exemplary steps of operatingthe circular stapler of FIG. 1;

FIG. 23A depicts a schematic view of an exemplary control circuit thatmay be incorporated into the circular stapler of FIG. 1, in a firststate of operation;

FIG. 23B depicts a schematic view of the control circuit of FIG. 23A, ina second state of operation;

FIG. 23C depicts a schematic view of the control circuit of FIG. 23A, ina third state of operation;

FIG. 23D depicts a schematic view of the control circuit of FIG. 23A, ina fourth state of operation;

FIG. 23E depicts a schematic view of the control circuit of FIG. 23A, ina fifth state of operation;

FIG. 23F depicts a schematic view of the control circuit of FIG. 23A, ina sixth state of operation;

FIG. 24 depicts a schematic view of an exemplary alternative controlcircuit that may be incorporated into the circular stapler of FIG. 1;

FIG. 25 depicts a schematic view of another exemplary alternativecontrol circuit that may be incorporated into the circular stapler ofFIG. 1; and

FIG. 26 depicts a schematic view of another exemplary alternativecontrol circuit that may be incorporated into the circular stapler ofFIG. 1.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the technology may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presenttechnology, and together with the description serve to explain theprinciples of the technology; it being understood, however, that thistechnology is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments, and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

I. Overview of Exemplary Circular Stapling Surgical Instrument

FIGS. 1-2 depict an exemplary surgical circular stapling instrument (10)that may be used to provide an end-to-end anastomosis between twosections of an anatomical lumen such as a portion of a patient'sdigestive tract. Instrument (10) of this example comprises a handleassembly (100), a shaft assembly (200), a stapling head assembly (300),and an anvil (400). Handle assembly (100) comprises a casing (110)defining an obliquely oriented pistol grip (112). In some versions,pistol grip (112) is perpendicularly oriented. In some other versions,pistol grip (112) is omitted. Handle assembly (110) further includes awindow (114) that permits viewing of a movable indicator needle (526) aswill be described in greater detail below. In some versions, a series ofhash marks, colored regions, and/or other fixed indicators arepositioned adjacent to window (114) in order to provide a visual contextfor indicator needle (526), thereby facilitating operator evaluation ofthe position of needle (526) within window (114). Various suitablealternative features and configurations for handle assembly (112) willbe apparent to those of ordinary skill in the art in view of theteachings herein.

Instrument (10) of the present example further includes a battery pack(120). Battery pack (120) is operable to provide electrical power to amotor (160) in pistol grip (112) as will be described in greater detailbelow. Battery pack (120) is removable from handle assembly (100). Inparticular, as shown in FIGS. 1-2, battery pack (120) may be insertedinto a socket (116) defined by casing (110). Once battery pack (120) isfully inserted in socket (116), latches (122) of battery pack (120) mayresiliently engage interior features of casing (110) to provide a snapfit. To remove battery pack (120), the operator may press latches (122)inwardly to disengage latches (122) from the interior features of casing(110) then pull battery pack (120) proximally from socket (116). Itshould be understood that battery pack (120) and handle assembly (100)may have complementary electrical contacts, pins and sockets, and/orother features that provide paths for electrical communication frombattery pack (120) to electrically powered components in handle assembly(100) when battery pack (120) is inserted in socket (116). It shouldalso be understood that, in some versions, battery pack (120) isunitarily incorporated within handle assembly (100) such that batteryback (120) cannot be removed from handle assembly (100).

Shaft assembly (200) extends distally from handle assembly (100) andincludes a preformed bend. In some versions, the preformed bend isconfigured to facilitate positioning of stapling head assembly (300)within a patient's colon. Various suitable bend angles or radii that maybe used will be apparent to those of ordinary skill in the art in viewof the teachings herein. In some other versions, shaft assembly (200) isstraight, such that shaft assembly (200) lacks a preformed bend. Variousexemplary components that may be incorporated into shaft assembly (100)will be described in greater detail below.

Stapling head assembly (300) is located at the distal end of shaftassembly (200). As shown in FIGS. 1-2 and as will be described ingreater detail below, anvil (400) is configured to removably couple withshaft assembly (200), adjacent to stapling head assembly (300). As willalso be described in greater detail below, anvil (400) and stapling headassembly (300) are configured to cooperate to manipulate tissue in threeways, including clamping the tissue, cutting the tissue, and staplingthe tissue. A knob (130) at the proximal end of handle assembly (100) isrotatable relative to casing (110) to provide precise clamping of thetissue between anvil (400) and stapling head assembly (300). When asafety trigger (140) of handle assembly (100) is pivoted away from afiring trigger (150) of handle assembly (100), firing trigger (150) maybe actuated to thereby provide cutting and stapling of the tissue.

A. Exemplary Anvil

In the following discussion of anvil (400), the terms “distal” and“proximal” (and variations thereof) will be used with reference to theorientation of anvil (400) when anvil (400) is coupled with shaftassembly (200) of instrument (10). Thus, proximal features of anvil(400) will be closer to the operator of instrument (10); while distalfeatures of anvil (400) will be further from the operator of instrument(10).

As best seen in FIGS. 3-5, anvil (400) of the present example comprisesa head (410) and a shank (420). Head (410) includes a proximal surface(412) that defines a plurality of staple forming pockets (414). Stapleforming pockets (414) are arranged in two concentric annular arrays. Insome other versions, staple forming pockets (414) are arranged in threeor more concentric annular arrays. Staple forming pockets (414) areconfigured to deform staples as the staples are driven into stapleforming pockets (414). For instance, each staple forming pocket (414)may deform a generally “U” shaped staple into a “B” shape as is known inthe art. As best seen in FIG. 4, proximal surface (412) terminates at aninner edge (416), which defines an outer boundary of an annular recess(418) surrounding shank (420).

Shank (420) defines a bore (422) and includes a pair of pivoting latchmembers (430) positioned in bore (422). As best seen in FIG. 5, eachlatch member (430) includes a “T” shaped distal end (432), a roundedproximal end (434), and a latch shelf (436) located distal to proximalend (434). “T” shaped distal ends (432) secure latch members (430)within bore (422). Latch members (430) are positioned within bore (422)such that distal ends (434) are positioned at the proximal ends oflateral openings (424), which are formed through the sidewall of shank(420). Lateral openings (424) thus provide clearance for distal ends(434) and latch shelves (436) to deflect radially outwardly from thelongitudinal axis defined by shank (420). However, latch members (430)are configured to resiliently bias distal ends (434) and latch shelves(436) to radially inwardly toward the longitudinal axis defined by shank(420). Latch members (430) thus act as retaining clips. This allowsanvil (400) to be removably secured to a trocar (330) of stapling headassembly (300) as will be described in greater detail below. It shouldbe understood, however, that latch members (436) are merely optional.Anvil (400) may be removably secured to a trocar (330) using any othersuitable components, features, or techniques.

In addition to or in lieu of the foregoing, anvil (400) may be furtherconstructed and operable in accordance with at least some of theteachings of U.S. Pat. Nos. 5,205,459; 5,271,544; 5,275,322; 5,285,945;5,292,053; 5,333,773; 5,350,104; 5,533,661; and/or 8,910,847, thedisclosures of which are incorporated by reference herein. Still othersuitable configurations will be apparent to one of ordinary skill in theart in view of the teachings herein.

B. Exemplary Stapling Head Assembly

As best seen in FIGS. 6-7, stapling head assembly (300) of the presentexample is coupled to a distal end of shaft assembly (200) and comprisesa tubular casing (310) housing a slidable staple driver member (350). Acylindraceous inner core member (312) extends distally within tubularcasing (310). Tubular casing (310) is fixedly secured to an outer sheath(210) of shaft assembly (200), such that tubular casing (310) serves asa mechanical ground for stapling head assembly (300).

Trocar (330) is positioned coaxially within inner core member (312) oftubular casing (310). As will be described in greater detail below,trocar (330) is operable to translate distally and proximally relativeto tubular casing (310) in response to rotation of knob (130) relativeto casing (110) of handle assembly (100). Trocar (330) comprises a shaft(332) and a head (334). Head (334) includes a pointed tip (336) and aninwardly extending proximal surface (338). Shaft (332) thus provides areduced outer diameter just proximal to head (334), with surface (338)providing a transition between that reduced outer diameter of shaft(332) and the outer diameter of head (334). While tip (336) is pointedin the present example, tip (336) is not sharp. Tip (336) will thus noteasily cause trauma to tissue due to inadvertent contact with tissue.Head (334) and the distal portion of shaft (332) are configured forinsertion in bore (422) of anvil (420). Proximal surface (338) and latchshelves (436) have complementary positions and configurations such thatlatch shelves (436) engage proximal surface (338) when shank (420) ofanvil (400) is fully seated on trocar (330). Anvil (400) is thus securedto trocar (330) through a snap fit due to latch members (430).

Staple driver member (350) is operable to actuate longitudinally withintubular casing (310) in response to activation of motor (160) as will bedescribed in greater detail below. Staple driver member (350) includestwo distally presented concentric annular arrays of staple drivers(352). Staple drivers (352) are arranged to correspond with thearrangement of staple forming pockets (414) described above. Thus, eachstaple driver (352) is configured to drive a corresponding staple into acorresponding staple forming pocket (414) when stapling head assembly(300) is actuated. It should be understood that the arrangement ofstaple drivers (352) may be modified just like the arrangement of stapleforming pockets (414) as described above. Staple driver member (350)also defines a bore (354) that is configured to coaxially receive coremember (312) of tubular casing (310). An annular array of studs (356)project distally from a distally presented surface surrounding bore(354).

A cylindraceous knife member (340) is coaxially positioned within stapledriver member (350). Knife member (340) includes a distally presented,sharp circular cutting edge (342). Knife member (340) is sized such thatknife member (340) defines an outer diameter that is smaller than thediameter defined by the inner annular array of staple drivers (352).Knife member (340) also defines an opening that is configured tocoaxially receive core member (312) of tubular casing (310). An annulararray of openings (346) formed in knife member (340) is configured tocomplement the annular array of studs (356) of staple driver member(350), such that knife member (340) is fixedly secured to staple drivermember (350) via studs (356) and openings (346). Other suitablestructural relationships between knife member (340) and stapler drivermember (350) will be apparent to those of ordinary skill in the art inview of the teachings herein.

A deck member (320) is fixedly secured to tubular casing (310). Deckmember (320) includes a distally presented deck surface (322) definingtwo concentric annular arrays of staple openings (324). Staple openings(324) are arranged to correspond with the arrangement of staple drivers(352) and staple forming pockets (414) described above. Thus, eachstaple opening (324) is configured to provide a path for a correspondingstaple driver (352) to drive a corresponding staple through deck member(320) and into a corresponding staple forming pocket (414) when staplinghead assembly (300) is actuated. It should be understood that thearrangement of staple openings (322) may be modified just like thearrangement of staple forming pockets (414) as described above. Itshould also be understood that various structures and techniques may beused to contain staples within stapling head assembly (300) beforestapling head assembly (300) is actuated. Such structures and techniquesthat are used to contain staples within stapling head assembly (300) mayprevent the staples from inadvertently falling out through stapleopenings (324) before stapling head assembly (300) is actuated. Varioussuitable forms that such structures and techniques may take will beapparent to those of ordinary skill in the art in view of the teachingsherein.

As best seen in FIG. 6, deck member (320) defines an inner diameter thatis just slightly larger than the outer diameter defined by knife member(340). Deck member (320) is thus configured to allow knife member (340)to translate distally to a point where cutting edge (342) is distal todeck surface (322).

In addition to or in lieu of the foregoing, stapling head assembly (300)may be further constructed and operable in accordance with at least someof the teachings of U.S. Pat. Nos. 5,205,459; 5,271,544; 5,275,322;5,285,945; 5,292,053; 5,333,773; 5,350,104; 5,533,661; and/or 8,910,847,the disclosures of which are incorporated by reference herein. Stillother suitable configurations will be apparent to one of ordinary skillin the art in view of the teachings herein.

C. Exemplary Shaft Assembly

FIG. 8 shows various components of shaft assembly (200), which couplescomponents of stapling head assembly (300) with components of handleassembly (100). In particular, and as noted above, shaft assembly (200)includes an outer sheath (210) that extends between handle assembly(100) and tubular casing (310). In the present example, outer sheath(210) is rigid and includes a preformed curved section as noted above.

Shaft assembly (200) further includes a trocar actuation rod (220) and atrocar actuation band assembly (230). The distal end of trocar actuationband assembly (230) is fixedly secured to the proximal end of trocarshaft (332). The proximal end of trocar actuation band assembly (230) isfixedly secured to the distal end of trocar actuation rod (220). Itshould therefore be understood that trocar (330) will translatelongitudinally relative to outer sheath (210) in response to translationof trocar actuation band assembly (230) and trocar actuation rod (220)relative to outer sheath (210). Trocar actuation band assembly (230) isconfigured to flex such that trocar actuation band assembly (230) mayfollow along the preformed curve in shaft assembly (200) as trocaractuation band assembly (230) is translated longitudinally relative toouter sheath (210). However, trocar actuation band assembly (230) hassufficient column strength and tensile strength to transfer distal andproximal forces from trocar actuation rod (220) to trocar shaft (332).Trocar actuation rod (220) is rigid. A clip (222) is fixedly secured totrocar actuation rod (220) and is configured to cooperate withcomplementary features within handle assembly (100) to prevent trocaractuation rod (220) from rotating within handle assembly (100) whilestill permitting trocar actuation rod (220) to translate longitudinallywithin handle assembly (100). Trocar actuation rod (220) furtherincludes a coarse helical threading (224) and a fine helical threading(226). Details regarding the movement of trocar actuation rod (220) willbe described in greater detail below.

Shaft assembly (200) further includes a stapling head assembly driver(240) that is slidably received within outer sheath (210). The distalend of stapling head assembly driver (240) is fixedly secured to theproximal end of staple driver member (350). The proximal end of staplinghead assembly driver (240) is secured to a drive bracket (250) via a pin(242). It should therefore be understood that staple driver member (350)will translate longitudinally relative to outer sheath (210) in responseto translation of stapling head assembly driver (240) and drive bracket(250) relative to outer sheath (210). Stapling head assembly driver(240) is configured to flex such that stapling head assembly driver(240) may follow along the preformed curve in shaft assembly (200) asstapling head assembly driver (240) is translated longitudinallyrelative to outer sheath (210). However, stapling head assembly driver(240) has sufficient column strength to transfer distal forces fromdrive bracket (250) to staple driver member (350). Details regarding themovement of drive bracket (250) will be described in greater detailbelow.

While not shown in FIG. 8, it should be understood that shaft assembly(200) may further include one or more spacer elements within outersheath (210). Such spacer elements may be configured to support trocaractuation band assembly (230) and/or stapling head assembly driver (240)as trocar actuation band assembly (230) and/or stapling head assemblydriver (240) translate through outer sheath (210). For instance, suchspacer elements may prevent trocar actuation band assembly (230) and/orstapling head assembly driver (240) from buckling as trocar actuationband assembly (230) and/or stapling head assembly driver (240) translatethrough outer sheath (210). Various suitable forms that such spacerelements may take will be apparent to those of ordinary skill in the artin view of the teachings herein.

In addition to or in lieu of the foregoing, shaft assembly (200) may befurther constructed and operable in accordance with at least some of theteachings of U.S. Pat. Nos. 5,205,459; 5,271,544; 5,275,322; 5,285,945;5,292,053; 5,333,773; 5,350,104; 5,533,661; and/or 8,910,847, thedisclosures of which are incorporated by reference herein. Still othersuitable configurations will be apparent to one of ordinary skill in theart in view of the teachings herein.

D. Exemplary Actuator Handle Assembly

As shown in FIG. 9, handle assembly (100) includes several componentsthat are operable to actuate anvil (400) and stapling head assembly(300). Handle assembly (100) also includes components that are operableto selectively lock out triggers (140, 150) based on the position ofanvil (400) relative to stapling head assembly (300). When triggers(140, 150) are locked out, firing trigger (150) is prevented frominitiating actuation of stapling head assembly (300). Thus, trigger(150) is only operable to initiate actuation of stapling head assembly(300) when the position of anvil (400) relative to stapling headassembly (300) is within a predefined range. The components of handleassembly (100) that provide the foregoing operability will be describedin greater detail below.

1. Exemplary Anvil Actuation Assembly

Knob (130) protrudes proximally from casing (110) of handle assembly andis rotatable relative to casing (110). As shown in FIG. 9, a nut (160)is secured to the distal end of knob (130). In the present example, nut(160) is fixedly secured to the distal end of knob (130) such that nut(160) will rotate unitarily with knob (130). Nut (160) and knob (130)are configured to cooperate with trocar actuation rod (220) to therebytranslate trocar actuation rod (220) longitudinally relative to casing(110) in response to rotation of nut (160) and knob (130) relative tocasing (110). As noted above, trocar (330) will translate longitudinallyrelative to outer sheath (210) in response to translation of trocaractuation rod (220) relative to outer sheath (210) and casing (110).

The proximal portion of trocar actuation rod (220) is positioned withinhandle assembly (100) to engage nut (160) and knob (130). In particular,trocar actuation rod (220) is positioned within handle assembly (100)such that coarse helical threading (224) will selectively engage athread engagement feature (not shown) within the interior of nut (160);and such that fine helical threading (226) will selectively engage athread engagement feature (not shown) within the interior of knob (130).In some versions, the thread engagement feature of nut (160) comprisesan inwardly directed tab; while the thread engagement feature of knob(130) comprises a helical threading. Other suitable forms that suchthread engagement features may take will be apparent to those ofordinary skill in the art in view of the teachings herein.

In the present example, when nut (160) and knob (130) are rotatedrelative to casing (110), trocar actuation rod (220) travels proximallythrough a first range of longitudinal motion where coarse helicalthreading (224) is engaged with nut (160) to provide a relatively rapidrate of translation. Fine helical threading (226) is not engaged withknob (130) during this range of motion. When nut (160) and knob (130)are further rotated relative to casing (110) after trocar actuation rod(220) completes the first range of motion, trocar actuation rod (220)will continue to travel proximally through a second range oflongitudinal motion where fine helical threading (226) is engaged withknob (130) to provide a relatively slow rate of translation. Thus,trocar actuation rod (220) will translate proximally through a sequenceof rapid translation followed by slow translation, based on engagementbetween coarse helical threading (224) and nut (160) followed byengagement between fine helical threading (226) and knob (130).

It should be understood that when anvil (400) is coupled with trocar(330), rotation of knob (130) will provide corresponding translation ofanvil relative to stapling head assembly (300). It should also beunderstood that knob (130) may be rotated in a first angular direction(e.g., clockwise) to retract anvil (400) toward stapling head assembly(300); and in a second angular direction (e.g., counterclockwise) toadvance anvil (400) away from stapling head assembly (300). Knob (130)may thus be used to adjust the gap distance (d) between opposingsurfaces (412, 322) of anvil (400) and stapling head assembly (300)until a suitable gap distance (d) has been achieved as shown in FIG. 21Cand as described in greater detail below.

2. Exemplary Trigger Lockout Assembly

As noted above, knob may be used to adjust the gap distance (d) betweenopposing surfaces (412, 322) of anvil (400) and stapling head assembly(300). Setting an appropriate gap distance (d) before actuating staplinghead assembly (300) may be critical to the success of an anastomosis.For instance, if the gap distance (d) is too great, the staples that aredeployed at the anastomosis site may not be sufficiently formed bystaple forming pockets (414). This may result in leakage at theanastomosis site, and in some cases may ultimately lead to theseparation of the anatomical lumen sections that are joined at theanastomosis site. If the gap distance (d) is too small, the internalstructure of the tissue compressed between surfaces (412, 322) may bedamaged to the point where the structural integrity of the tissue iscompromised. This may prevent the tissue from adequately holding theformed staples, which again may result in leakage or other failure ofthe anastomosis. It may therefore be desirable to provide the operatorwith some form of feedback indicating whether the gap distance (d) iswithin an appropriate range. It may also be desirable to prevent theoperator from actuating stapling head assembly (300) unless the gapdistance (d) is within an appropriate range.

FIGS. 9-12E show components that provide feedback to the operator toindicate whether the gap distance (d) is within an appropriate range;and prevent the operator from actuating stapling head assembly (300)unless the gap distance (d) is within an appropriate range. As best seenin FIGS. 12B-12C, a bracket (500) is configured and positioned to movein response to movement of trocar actuation rod (220). As best seen inFIG. 10, bracket (500) includes a rigid body (502) that defines a firstslot (504), a second slot (506), and a third slot (508). An uprightfeature (510) is positioned at the proximal end of body (502) anddefines an opening (512). Trocar actuation rod (220) extends coaxiallythrough opening (512). As shown in FIG. 9, a coil spring (170) isinterposed between the proximal end of upright feature (510) and a rigidbulkhead feature that is defined by casing (110) and that forms asupport journal for nut (160). The bulkhead is fixed within casing (110)and thereby provides a ground for the proximal end of coil spring (170),such that coil spring (170) resiliently imparts a distal bias to bracket(500) via upright feature (510). Bracket (500) further includes alaterally presented flange (516) at the distal end of body (502). Flange(516) defines a slot (514).

As best seen in FIGS. 12B-12C, an indicator member (520) is configuredto pivot in response to translation of bracket (500). As best seen inFIG. 11, indicator member (520) comprises an upright arm (522), a snappin (524) projecting laterally from a lower end of arm (522), anindicator needle (526) projecting laterally from an upper end of arm(522), and a coupling pin (528) projecting laterally from anintermediate region of arm (522). Snap pin (524) is configured to snapinto a complementary recess provided by casing (110). Snap pin (524)thereby secures indicator member (520) to casing (110) yet permitsindicator member (520) to pivot relative to casing (110) about thelongitudinal axis of snap pin (524). Indicator needle (526) ispositioned to be visible through window (114) of handle assembly (110)to thereby visually indicate the pivotal position of indicator member(520). Coupling pin (528) is slidably received in slot (514) of flange(516) of bracket (500). This engagement between indicator member (520),casing (110), and bracket (500) provides pivotal movement of indicatormember (520) in response to translation of bracket (500).

Bracket (500) is configured to selectively prevent and permit actuationof triggers (140, 150). In particular, slots (504, 506) of bracket (500)are configured to selectively provide clearance for actuation oftriggers (140, 150). As shown in FIGS. 12A-12E, safety trigger (140) ispivotably coupled with a first upright member (144). First uprightmember (144) is coupled with casing (110) such that first upright member(144) is configured to translate upwardly in response to pivoting ofsafety trigger (140) toward pistol grip (112). However, body (502) ofbracket (500) is configured to prevent this movement of first uprightmember (144) and safety trigger (140) by engaging the upper end (146) offirst upright member (144). Body (502) thus blocks movement of firstupright member (144) and safety trigger (140) until bracket (500) ismoved to a position where slot (506) is aligned with upper end (146) tothereby provide clearance for upward movement of first upright member(144). It should therefore be understood that safety trigger (140)cannot be pivoted toward pistol grip (112) until slot (506) ispositioned over upper end (146).

Similarly, firing trigger (150) is pivotably coupled with a secondupright member (154). Second upright member (154) is coupled with casing(110) such that second upright member (154) is configured to translateupwardly in response to pivoting of safety trigger (150) toward pistolgrip (112). However, body (502) of bracket (500) is configured toprevent this movement of second upright member (154) and firing trigger(150) by engaging the upper end (156) of second upright member (154).Even if safety trigger (140) is pivoted out of the way to otherwisepermit movement of firing trigger (150), body (502) blocks movement ofsecond upright member (154) and firing trigger (150) until bracket (500)is moved to a position where slot (504) is aligned with upper end (156)to thereby provide clearance for upward movement of second uprightmember (154). It should therefore be understood that, even if safetytrigger (140) is pivoted out of the way to otherwise permit movement offiring trigger (150), firing trigger (150) cannot be pivoted towardpistol grip (112) until slot (504) is positioned over upper end (156).

Third slot (508) is configured to receive a downwardly projecting boss(223) of clip (222), which is rigidly secured to trocar actuation rod(220). While casing (110) is configured to allow bracket (500) totranslate longitudinally within casing (110), casing (110) includesrails, channels, and/or other features that prevent bracket (500) fromrotating within casing (110). Thus, the positioning of boss (223) inslot (508) prevents clip (222) and trocar actuation rod (220) fromrotating within casing (110). Boss (223) and slot (508) neverthelessallow bracket (500) to translate longitudinally within casing (110) aswill be described in greater detail below.

FIGS. 12A-12E depict the above-described components at various stages ofoperation. In particular, in FIG. 12A, trocar actuation rod (220) is ina distal-most position, such that trocar (330) is in a distal-mostposition. At this stage, the operator may couple anvil (400) with trocar(330) by inserting trocar (330) into bore (422) until latch members(430) are secured to head (334) of trocar (330). The operator thenrotates knob (130), which rotates nut (160). As knob (130) and nut (160)rotate, engagement between coarse helical threading (224) of trocaractuation rod (220) and the complementary feature of nut (160) causestrocar actuation rod (220) to retract proximally at a relatively rapidrate, such that trocar actuation rod (220) reaches the position shown inFIG. 12B. This provides proximal retraction of trocar actuation rod(220) provides retraction of trocar (330) and anvil (400). As trocaractuation rod (220) moves from the position shown in FIG. 12A to theposition shown in FIG. 12B, bracket (500) remains stationary. This isdue to the fact that clip (222) is spaced apart from upright feature(510) at the stage shown in FIG. 12A and does not engage upright feature(510) until trocar actuation rod (220) reaches the position shown inFIG. 12B.

After reaching the stage shown in FIG. 12B, the operator may continuerotating knob (130) and nut (160), which causes further proximalretraction of trocar actuation rod (220) as shown in FIG. 12C. This ofcourse causes further proximal retraction of trocar (330) and anvil(400). As trocar actuation rod (220) moves from the position shown inFIG. 12B to the position shown in FIG. 12C, clip (222) bears againstbracket (500), driving bracket (500) proximally. This proximal movementof bracket (500) causes indicator member (520) to pivot from theposition shown in FIG. 12B to the position shown in FIG. 12C due to thepositioning of pin (528) in slot (514) of flange (516).

As indicator member (520) pivots from the position shown in FIG. 12B tothe position shown in FIG. 12C, the operator may observe the position ofindicator needle (526) through window (114) of handle assembly (110). Asnoted above, a series of hash marks, colored regions, and/or other fixedindicators may be positioned adjacent to window (114) in order toprovide a visual context for indicator needle (526), therebyfacilitating operator evaluation of the position of needle (526) withinwindow (114). It should be understood that the position of needle (526)within window (114) will be indicative of the longitudinal position oftrocar (330) and anvil (400). The position of needle (526) within window(114) will thus indicate the gap distance (d) between opposing surfaces(412, 322) of anvil (400) and stapling head assembly (300). Whileobserving the position of needle (526) within window (114), the operatormay rotate knob (130) clockwise or counterclockwise to further retractor advance trocar (330) and anvil (400), thereby providing fineadjustment of the gap distance (d) until a desired gap distance (d) isreached within an appropriate range.

In order to provide fine control of the gap distance (d) adjustment atthe stage shown in FIG. 12C, trocar actuation rod (220) will be at alongitudinal position where fine helical threading (226) is engaged witha complementary feature of knob (130) and coarse helical threading (224)is disengaged from the complementary feature of nut (160). In someversions, coarse helical threading (224) disengages nut (160) and finehelical threading (226) begins to engage knob (130) once trocaractuation rod (220) reaches the longitudinal position shown in FIG. 12B(i.e., when clip (222) first engages upright member (510)). In someother versions, the transition from engagement by coarse helicalthreading (224) to fine helical threading (226) occurs sometime betweenthe stage shown in FIG. 12B and the stage shown in FIG. 12C. Othersuitable stages at which the coarse-to-fine transition may occur will beapparent to those of ordinary skill in the art in view of the teachingsherein. It should also be understood that some alternative versions oftrocar actuation rod (220) may have just a single threading section,with the pitch of the threading being consistent along the length of thethreading. In other words, trocar actuation rod (220) does notnecessarily need to have two different sections of threading (224, 226)with different pitches.

At the stage shown in FIG. 12C, slot (506) is aligned with upper end(146) to thereby provide clearance for upward movement of first uprightmember (144). Similarly, slot (504) is aligned with upper end (156) tothereby provide clearance for upward movement of second upright member(154). In the present example, slots (504, 506) are sized and positionedsuch that slots (504, 506) only provide clearance for upward movement ofupright members (144, 154) when the gap distance (d) is within aclinically acceptable range. By way of example only, a “clinicallyacceptable range” for the gap distance (d) may be between approximately0.110 inches and approximately 0.040 inches. As another merelyillustrative example, a “clinically acceptable range” for the gapdistance (d) may be between approximately 0.110 inches and approximately0.020 inches. Even when slots (504, 506) are positioned to provideclearance for upward movement of upright members (144, 154) as shown inFIG. 12C, safety trigger (140) will still block pivotal movement offiring trigger (150) about a pin (152) (FIG. 9) when safety trigger(140) is in the non-actuated position shown in FIG. 12C. Thus, in orderto enable movement of firing trigger (150), the operator will need tofirst actuate safety trigger (140) about a pin (142) (FIG. 9) from theposition shown in FIG. 12C to the position shown in FIG. 12D.

As shown in FIG. 12D, upper end (146) passes through slot (506) assafety trigger (140) is pivoted from the position shown in FIG. 12C tothe position shown in FIG. 12D. It should be understood that thismovement of upper end (146) would not be possible at the stages shown inFIGS. 12A-12B (when the gap distance (d) is too great) because body(502) would physically block upward movement of upright member (144),thereby physically blocking pivotal movement of safety trigger (140). Inthe present example, a cap (not shown) incorporated into knob (130)prevents knob (130) from rotating to a point where anvil (400) would beretracted too far proximally (such that the gap distance (d) is toosmall). In some other variations, even if knob (130) were to permitanvil (400) to be retracted too far proximally (such that the gapdistance (d) is too small), body (502) would physically block upwardmovement of upright member (144), thereby physically blocking pivotalmovement of safety trigger (140), in the event that the operatorretracts trocar (330) and anvil (400) too far proximally (such that thegap distance (d) is too small). Regardless of whether body (502), knob(130), or some other feature prevents actuation when the gap distance(d) would be too small, it should be understood that instrument (10)permits actuation of safety trigger (140) only when the gap distance (d)is within the clinically acceptable range.

As noted above, safety trigger (140) is configured to prevent actuationof firing trigger (150) until safety trigger (140) has been actuated.Once safety trigger (140) has been actuated, the operator may actuatefiring trigger (150) from the position shown in FIG. 12D to the positionshown in FIG. 12E. As shown in FIG. 12E, upper end (156) passes throughslot (504) as firing trigger (150) is pivoted from the position shown inFIG. 12D to the position shown in FIG. 12E. It should be understoodthat, even in the complete absence of safety trigger (140), thismovement of upper end (156) would not be possible at the stages shown inFIGS. 12A-12B (when the gap distance (d) is too great) because body(502) would physically block upward movement of upright member (154),thereby physically blocking pivotal movement of firing trigger (150). Itshould also be understood that body (502) would also physically blockupward movement of upright member (154), thereby physically blockingpivotal movement of firing trigger (150), in the event that the operatorretracts trocar (330) and anvil (400) too far proximally (such that thegap distance (d) is too small). Thus, even in the complete absence ofsafety trigger (140), firing trigger (150) may only be actuated when thegap distance (d) is within the clinically acceptable range.

Firing trigger (150) of the present example includes an integralactuation paddle (158). Paddle (158) pivots forwardly as firing trigger(150) pivots from the position shown in FIG. 12D to the position shownin FIG. 12E. Paddle (158) is configured to actuate a switch of a motoractivation module (180), which is shown in FIG. 9, when firing trigger(150) pivots from the position shown in FIG. 12D to the position shownin FIG. 12E. Motor activation module (180) is in communication withbattery pack (120) and motor (160), such that motor activation module(180) is configured to provide activation of motor (160) with electricalpower from battery pack (120) in response to paddle (158) actuating theswitch of motor activation module (180). Thus, motor (160) will beactivated when firing trigger (150) is pivoted from the position shownin FIG. 12D to the position shown in FIG. 12E. This activation of motor(160) will actuate stapling head assembly (300) as described in greaterdetail below.

3. Exemplary Stapling Head Actuation Assembly

FIGS. 13-20D show various components that are operable to actuatestapling head assembly (300). These components include motor (160), agearbox (162), a rotary cam member (700), a cam follower (600), drivebracket (250) and stapling head assembly driver (240). Gearbox (162) iscoupled with a drive shaft of motor (160) and is further coupled withcam member (700). Activation of motor (160) thus causes rotation of cammember (700) via gearbox (162). Various suitable configurations that maybe used for gearbox (162) will be apparent to those of ordinary skill inthe art in view of the teachings herein. Cam member (700) is configuredto interact with cam follower (160) to pivot cam follower (160) in twoangular directions about a pin (118) as will be described in greaterdetail below. Pin (118) is coupled with casing (110). A bushing (701)provides rotary support to cam member (700) relative to casing (110).

Cam follower (600) is pivotably coupled with drive bracket (250) via apair of integral pins (602), which are received in complementary notches(252) of drive bracket (250). As shown in FIGS. 14-15, cam follower(600) includes a first bearing feature (604) and a second bearingfeature (610). First bearing feature (604) consists of a rounded,horizontally extending surface. Second bearing feature (610) is shapedlike a quarter-pie defined by a straight vertical surface (612), ahorizontally extending surface (614), and a curved surface (616). Secondbearing feature (610) projects proximally relative to first bearingfeature (504).

FIGS. 16-17 show cam member (700) in greater detail. Cam member (700)comprises a distal face (702), a distally projecting post (704), and anouter circumferential surface (706). A first cam feature (710) and asecond cam feature (720) project distally from distal face (702). Post(704) engages bushing (701). First cam feature (710) comprises a firstsurface region (712), a second surface region (714), and a third surfaceregion (716). First surface region (712) is convexly defined by arelatively large radius of curvature, such that first surface region(712) is nearly flat. Second surface region (714) is convexly defined bya progressively increasing radius of curvature. Third surface region(716) is concavely defined by a relatively large radius of curvature. Inaddition to projecting distally from distal face (702), second camfeature (720) projects outwardly from outer circumferential surface(706). Second cam feature (720) includes a first surface region (722)and a second surface region (724). First surface region (722) issubstantially flat while second surface region (724) is concavelycurved. The origin of the radius of curvature for each curved surfaceregion (712, 714, 716, 724) is offset from the center of post (704).

FIGS. 18A-18B show the general interaction between cam follower (600)and first and second cam features (710, 720), though this interactionwill be described in greater detail below with reference to FIGS.20A-20D. As cam member (700) is rotated from the position shown in FIG.18A to the position shown in FIG. 18B, first cam feature (710) bearsagainst first bearing feature (604) of cam follower (600), causing camfollower to pivot about pin (118). In the view shown in FIGS. 18A-18B,cam follower (600) pivots counterclockwise as cam member (700) isrotated from the position shown in FIG. 18A to the position shown inFIG. 18B. As can be seen in the transition from FIG. 18A to FIG. 18B,this counterclockwise pivoting of cam follower (600) drives drivebracket (250) and stapling head assembly driver (240) distally, therebyactuating stapling head assembly (300). As cam member (700) continues torotate in the same direction back toward the position shown in FIG. 18A,second cam feature (720) engages and bears against second bearingfeature (610) of cam follower (600), causing cam follower (600) to pivotclockwise about pin (118). This clockwise pivoting of cam follower (600)about pin (118) retracts drive bracket (250) and stapling head assemblydriver (240) proximally back toward the position shown in FIG. 18A.

Referring back to FIGS. 16-17, a third cam feature (730) projectsoutwardly from outer circumferential surface (706). Third cam feature(730) comprises a first surface region (732) and a second surface region(734). First surface region (732) is flat and is oriented generallytangentially relative to outer circumferential surface (706). Secondsurface region (732) is also flat and is oriented radially outwardlyrelative to outer circumferential surface (706). Third cam feature (730)is configured to interact with a rocker member (800) as shown in FIGS.19A-19B. Rocker member (800) comprises an integral pin (802), a bearingmember (804), and a paddle (806). Pin (802) is pivotably coupled withcasing (110), such that rocker member (800) is pivotable within casing(110) about the longitudinal axis defined by pin (802). Bearing member(804) is configured to interact with third cam feature (730) as will bedescribed in greater detail below. Paddle (806) is configured to actuatea switch button (192) of a short circuit module (190) as will also bedescribed in greater detail below.

FIG. 19A shows cam member (700) in the same position as shown in FIG.18A. At this stage, second surface region (734) of third cam feature(730) is adjacent to bearing member (804) of rocker member (800). FIG.19B shows cam member (700) in a position where cam member (700) has beenrotated past the position shown in FIG. 18B and back toward the positionshown in FIG. 18A. However, cam member (700) has not completed a fullrevolution. At the stage shown in FIG. 19B, first surface region (732)has engaged and borne against bearing member (804), thereby pivotingrocker member (800) about the longitudinal axis defined by pin (802).This has caused paddle (806) to actuate switch button (192) of shortcircuit module (190). Short circuit module (190) is configured toprevent motor (160) from further activation when switch button (192) hasbeen actuated. In some versions, short circuit module (190) couplesbattery pack (120) with a power sink, in addition to short circuitingmotor (160), when switch button (192) is actuated. This may result indischarge of battery pack (120) in addition to stopping activation ofmotor (160) once an actuation stroke of stapling head assembly (300) hasbeen completed. By way of example only, short circuit module (190) maybe configured and operable in accordance with at least some of theteachings of U.S. Pub. No. 2015/0083774, the disclosure of which isincorporated by reference herein. Other suitable configurations will beapparent to those of ordinary skill in the art in view of the teachingsherein.

FIGS. 20A-20D schematically depict the interaction between cam member(700), features of cam follower (600), and features of rocker member(800) as cam member (700) rotates. It should be understood that therotation of cam member (700) throughout the stages shown in FIGS.20A-20D is driven by motor (160) and gearbox (162). FIG. 20A shows cammember (700) in the same position as shown in FIGS. 18A and 19A. At thisstage, first bearing feature (604) of cam follower (600) is positionedon first surface region (712) and bearing member (804) or rocker member(800) is adjacent to second surface region (734) of third cam feature(730). Also at this stage, knife member (340) and staple driver member(350) are in proximal positions, such that stapling head assembly (300)is in a non-actuated state. As cam member (700) is rotated to theposition shown in FIG. 20B, second surface region (714) bears againstbearing member (804), thereby driving bearing member (804) upwardly.This causes cam follower (600) to pivot about pin (118) to the positionshown in FIG. 18B. Cam follower (600) thus drives knife member (340) andstaple driver member (350) distally via drive bracket (250) and staplinghead assembly driver (240). Stapling head assembly (300) is thus in anactuated state at the stage shown in FIG. 20B. In some versions, cammember (700) rotates through an angular range of approximately 270° inorder to transition stapling head assembly (300) from the non-actuatedstate to the actuated state.

After stapling head assembly (300) has been actuated, cam member (700)continues to rotate to the position shown in FIG. 20C. At this stage,first surface region (722) of second cam member (720) begins to engagecurved surface (616) of second bearing feature (610) of cam follower(600). As cam member (700) continues to rotate to the position shown inFIG. 20D, second surface region (724) engages curved surface (616) ofsecond bearing feature (610), driving second bearing feature (610)downwardly. This causes cam follower (600) to pivot about pin (118) backfrom the position shown in FIG. 18B toward the position shown in FIG.18A. Cam follower (600) thus drives knife member (340) and staple drivermember (350) proximally via drive bracket (250) and stapling headassembly driver (240). In addition, first surface region (732) hasengaged and borne against bearing member (804), thereby pivoting rockermember (800) about the longitudinal axis defined by pin (802) at thestage shown in FIG. 20D. Rocker member (800) is thus in the same statein FIG. 20D as shown in FIG. 19B. Short circuit module (190) has thusbeen actuated at the stage shown in FIG. 20D.

It should be understood from the foregoing that cam member (700) isoperable to drive knife member (340) and staple driver member (350)distally, then drive knife member (340) and staple driver member (350)proximally and actuate short circuit module (190) by rotating in asingle angular direction through the range of motion shown in FIGS.20A-20D. Other suitable ways in which knife member (340), staple drivermember (350), and short circuit module (190) may be actuated will beapparent to those of ordinary skill in the art in view of the teachingsherein.

E. Exemplary Anastomosis Procedure

FIGS. 21A-21E show instrument (10) being used to form an anastomosis(70) between two tubular anatomical structures (20, 40). By way ofexample only, the tubular anatomical structures (20, 40) may comprisesections of a patient's esophagus, sections of a patient's colon, othersections of the patient's digestive tract, or any other tubularanatomical structures. As shown in FIG. 21A, anvil (400) is positionedin one tubular anatomical structure (20) and stapling head assembly(300) is positioned in another tubular anatomical structure (40). Inversions where tubular anatomical structures (20, 40) comprise sectionsof a patient's colon, stapling head assembly (300) may be inserted viathe patient's rectum. It should also be understood that the proceduredepicted in FIGS. 21A-21E is an open surgical procedure, though theprocedure may instead be performed laparoscopically. Various suitableways in which instrument (10) may be used to form an anastomosis (70) ina laparoscopic procedure will be apparent to those of ordinary skill inthe art in view of the teachings herein.

As shown in FIG. 21A, anvil (400) is positioned in tubular anatomicalstructure (20) such that shank (420) protrudes from the open severed end(22) of tubular anatomical structure (20). A purse-string suture (30) isprovided about a mid-region of shank (420) to generally secure theposition of anvil (400) in tubular anatomical structure (20). Similarly,stapling head assembly (300) is positioned in tubular anatomicalstructure (40) such that trocar (330) protrudes from the open severedend (42) of tubular anatomical structure (20). A purse-string suture(50) is provided about a mid-region of shaft (332) to generally securethe position of stapling head assembly (300) in tubular anatomicalstructure (40).

Next, anvil (400) is secured to trocar (330) by inserting trocar (330)into bore (422) as shown in FIG. 21B. Latch members (430) engage head(334) of trocar (330), thereby providing a secure fit between anvil(400) and trocar (330). The operator then rotates knob (130) whileholding casing (110) stationary via pistol grip (112). This rotation ofknob (130) causes trocar (330) and anvil (400) to retract proximally (asdescribed above with reference to FIGS. 12A-12C). As shown in FIG. 21C,this proximal retraction of trocar (330) and anvil (400) compresses thetissue of tubular anatomical structures (20, 40) between surfaces (412,322) of anvil (400) and stapling head assembly (300). The operatorobserves the position of needle (526) within window (114) to determinewhether the gap distance (d) between opposing surfaces (412, 322) ofanvil (400) and stapling head assembly (300) is appropriate; and makesany necessary adjustments via knob (130).

Once the operator has appropriately set the gap distance (d) via knob(130), the operator actuates safety trigger (140) (as shown in FIG. 12D)to enable actuation of firing trigger (150). The operator then actuatesfiring trigger (150) (as shown in FIG. 12D). This causes paddle (158) toactuate the switch of a motor activation module (180), therebyactivating motor to rotate cam member (700) (as shown in FIGS. 20A-20D).This rotation of cam member (700) actuates stapling head assembly (300)by driving knife member (340) and staple driver member (350) distally asshown in FIG. 21D. As knife member (340) translates distally, cuttingedge (342) of knife member (340) cooperates with inner edge (416) ofanvil (400), thereby shearing excess tissue that is positioned withinannular recess (418) of anvil (400) and the interior of knife member(340).

As shown in FIG. 4, anvil (400) of the present example includes abreakable washer (417) within annular recess (418). This washer (417) isbroken by knife member (340) when the knife member (340) completes afull distal range of motion from the position shown in FIG. 21C to theposition shown in FIG. 21D. The progressively increasing radius ofcurvature of second surface region may provide an increasing mechanicaladvantage as knife member (340) reaches the end of its distal movement,thereby providing greater force by which to break the washer (417). Ofcourse, the breakable washer (417) may be omitted entirely in someversions. In versions where washer (417) is included, it should beunderstood that washer (417) may also serve as a cutting board for knifemember (340) to assist in cutting of tissue. Such a cutting techniquemay be employed in addition to or in lieu of the above-noted shearingaction between inner edge (416) and knife member (340).

As staple driver member (350) translates distally from the positionshown in FIG. 21C to the position shown in FIG. 21D, staple drivermember (350) drives staples (90) through the tissue of tubularanatomical structures (20, 40) and into staple forming pockets (414) ofanvil (400). Staple forming pockets (414) deform the driven staples (90)into a “B” shape as is known in the art. The formed staples (90) thussecure the ends of tissue together.

After the operator has actuated stapling head assembly (300) as shown inFIG. 21D, the operator rotates knob (130) to drive anvil (400) distallyaway from stapling head assembly (300), increasing the gap distance (d)to facilitate release of the tissue between surfaces (412, 322). Theoperator then removes instrument (10) from the patient, with anvil (400)still secured to trocar (330). Referring back to the example where thetubular anatomical structures (20, 40) comprise sections of a patient'scolon, instrument (10) may be removed via the patient's rectum. Withinstrument (10) is removed, the tubular anatomical structures (20, 40)are left secured together by two annular arrays of staples (90) at ananastomosis (70) as shown in FIG. 21E. The inner diameter of theanastomosis (70) is defined by the severed edge (60) left by knifemember (340).

II. Exemplary Routines for Surgical Stapler

While the sequence described above with reference to FIGS. 21A-21Erelate to how instrument (10) may be used by an operator in a surgicalprocedure, it should be understood that there are various routines thatmay be performed within instrument (10) before, during, and after theprocedure depicted in FIGS. 21A-21E. FIGS. 22A-22B show various steps inan exemplary process (4000) that may be carried out through instrument(10) before, during, and after the procedure depicted in FIGS. 21A-21E.It should be understood that various steps of process (4000) are merelyoptional and may be omitted if desired.

In the present example, process (4000) begins with an operator insertingbattery pack (120) into socket (116) of handle assembly (100), as shownin block (4002). In some versions, the insertion of battery back (120)into socket (116) will automatically trigger one or more additionalsteps in process (4000). For instance, as shown in block (4004), theinsertion of battery back (120) into socket (116) may automaticallyactivate a drain switch that begins to drain power from battery pack(120). By way of example only, such automatic drainage of power frombattery pack (120) may be provided in accordance with at least some ofthe teachings of U.S. Patent App. No. [ATTORNEY DOCKET NO. END7583USNP.0622770], entitled “Surgical Stapler with Ready State Indicator,” filedon even date herewith, the disclosure of which is incorporated byreference herein. In addition or in the alternative, automatic drainageof power from battery pack (120) may be provided in accordance with atleast some of the teachings below with reference to FIGS. 23A-23F. Othersuitable ways in which power may be automatically drained from batterypack (120) upon insertion of battery back (120) into socket (116) willbe apparent to those of ordinary skill in the art in view of theteachings herein. Alternatively, in some versions the step shown inblock (4004) is simply omitted.

In addition to or as an alternative to automatically initiating drainageof power from battery pack (120), the insertion of battery pack (120)into socket (116) may also mechanically unlock the ability to retracttrocar (330) and anvil (400) proximally, as shown in block (4006). Byway of example only, such unlocking of the ability to retract trocar(330) and anvil (400) proximally may be provided in accordance with atleast some of the teachings of U.S. Patent App. No. [ATTORNEY DOCKET NO.END7583USNP. 0622770], entitled “Surgical Stapler with Ready StateIndicator,” filed on even date herewith, the disclosure of which isincorporated by reference herein. Other suitable ways in which theability to retract trocar (330) and anvil (400) proximally may beautomatically unlocked upon insertion of battery back (120) into socket(116) will be apparent to those of ordinary skill in the art in view ofthe teachings herein. Alternatively, in some versions the step shown inblock (4006) is simply omitted.

It should also be understood that the insertion of battery pack (120)into socket (116) may provide a necessary electrical connection withinthe circuit that actuates stapling head assembly (300), as shown inblock (4008). In other words, in the absence of battery pack (120), thecircuit that actuates stapling head assembly will lack a necessaryelectrical connection. In some other versions, instrument (10) iscapable of receiving electrical power from some other source, such thatbattery pack (120) need not necessarily be inserted into socket (116) inorder to complete a circuit that is operable to actuate stapling headassembly (300).

In some versions, the insertion of battery pack (120) into socket (116)may also mechanically unlock the ability to actuate safety trigger(140), as shown in block (4010). Various suitable ways in which theinsertion of battery pack (120) into socket (116) may mechanicallyunlock the ability to actuate safety trigger (140) will be apparent tothose of ordinary skill in the art in view of the teachings herein.Alternatively, in some versions the step shown in block (4010) is simplyomitted.

Regardless of whether (or the extent to which) the steps shown in blocks(4004, 4006, 4008, 4010) are ultimately included in process (4000),process (400) may proceed with insertion of anvil (400) into anatomicalstructure (20), as shown in block (4012). This step is also shown inFIG. 21A as discussed above. Continuing on with process (4000) as shownin FIGS. 22A-22B, anvil (400) is then secured to trocar (330) as shownin block (4014). This step is also shown in FIG. 21B as discussed above.Continuing on with process (4000) as shown in FIGS. 22A-22B, anvil (400)and trocar (330) are then retracted proximally to compress the tissue ofanatomical structures (20, 40), as shown in block (4016). This step isalso shown in FIG. 21C as discussed above. The operator rotates knob(130) in order to achieve an appropriate gap distance (d), as shown inblock (4018). This step is also shown in FIGS. 12B-12C and 21C asdiscussed above.

In some instances, instrument (10) includes electromechanical featuresthat monitor the gap distance (d) and provide feedback to the operatorrelating to the gap distance (d). By way of example only, such featuresmay be provided in accordance with at least some of the teachings ofU.S. Patent App. No. [ATTORNEY DOCKET NO. END7583USNP. 0622770],entitled “Surgical Stapler with Ready State Indicator,” filed on evendate herewith, the disclosure of which is incorporated by referenceherein. Other suitable ways in which an instrument (10) may monitor thegap distance (d) and provide feedback to the operator relating to thegap distance (d) will be apparent to those of ordinary skill in the artin view of the teachings herein. For those versions of instrument (10)that do have this capability, process (4000) includes such monitoring ofthe gap distance (d) as shown in block (4020). Instrument (10) mayprovide audible, visual, and or tactile feedback relating to the gapdistance (d) as shown in block (4022). In the event that the gapdistance (d) falls below the clinically acceptable range (i.e., anvil(400) is getting too close to stapling head assembly (300)), instrument(10) my provide an indication to the operator to indicate that anvil(400) needs to be advanced distally to increase the gap distance (d), asshown in block (4024).

Regardless of whether instrument (10) includes electromechanicalfeatures that monitor the gap distance (d) and provide feedback to theoperator relating to the gap distance (d), bracket (500) will move to aposition where it unblocks actuation of safety trigger (140) when thegap distance (d) reaches the clinically acceptable range, as shown inblock (4026). Such positioning of bracket (500) is also shown in FIG.12C as described above. The operator may actuate safety trigger (140)once bracket (500) has moved into the unblocking position, as shown inblock (4028). Such actuation of safety trigger (140) is also shown inFIG. 12D as described above. Once safety trigger (130) has beenactuated, the operator may then actuate firing trigger (150), as shownin block (4030). Such actuation of firing trigger (150) is also shown inFIG. 12E as described above.

Once the operator actuates firing trigger (150), instrument (10) willcomplete an actuation stroke of stapling head assembly (300), regardlessof what the operator does next with firing trigger (150), as shown inblock (4032). In other words, the assembly that actuates stapling headassembly (300) (i.e., motor (160) and the rest of the components thatcouple motor (160) with stapling head assembly (300)) will effectivelybe fully committed to actuating stapling head assembly (300) once theoperator actuates firing trigger (150), even if the operator furthermanipulates firing trigger (150). By way of example only, instrument(10) may include components that provide full commitment to theactuation of stapling head assembly (300) in response to actuation offiring trigger (150) in accordance with at least some of the teachingsof U.S. Pub. No. 2015/0083774, entitled “Control Features for MotorizedSurgical Stapling Instrument,” published Mar. 26, 2015, the disclosureof which is incorporated by reference herein. Alternatively, instrument(10) may include components that provide full commitment to theactuation of stapling head assembly (300) in response to actuation offiring trigger (150) in accordance with the teachings below.

The actuation stroke of stapling head assembly (300) includes the distaland proximal motion of various components, as shown in block (4034).This alternating motion is shown in FIGS. 18A-18B and in FIGS. 20A-20Das described above. The distal motion is also shown in FIG. 21D asdescribed above.

In some versions of instrument (10), while the firing mechanismcompletes the actuation stroke of stapling head assembly (300),instrument (10) may include features that detect strain within thefiring mechanism as shown in block (4036). By way of example only, suchsensing may be provided in accordance with at least some of theteachings of U.S. Patent App. No. [ATTORNEY DOCKET NO.END7585USNP.0622773], entitled “Surgical Stapler with Incomplete FiringIndicator,” filed on even date herewith, the disclosure of which isincorporated by reference herein. Other suitable ways in whichinstrument (10) may incorporate features that sense strain in the firingsystem be apparent to those of ordinary skill in the art in view of theteachings herein. Alternatively, such features may be omitted such thatthe step shown in block (4036) is omitted. In the event that suchfeatures are included, instrument (10) may provide an audible, visual,and/or tactile indication in the event that the sensing feature(s)detected that the strain has exceeded a threshold, as shown in block(4038).

In addition to or as an alternative to features that detect strain inthe firing mechanism during the actuation stroke of stapling headassembly (300), some versions of instrument (10) may include a switch orother kind of sensor that detects whether a portion of the firingmechanism has traveled to an expected distance during the actuationstroke, as indicated in block (4040). By way of example only, suchsensing may be provided in accordance with at least some of theteachings of U.S. Patent App. No. [ATTORNEY DOCKET NO.END7585USNP.0622773], entitled “Surgical Stapler with Incomplete FiringIndicator,” filed on even date herewith, the disclosure of which isincorporated by reference herein. Other suitable ways in whichinstrument (10) may incorporate features that sense whether the firingmechanism has completed sufficient travel will be apparent to those ofordinary skill in the art in view of the teachings herein.Alternatively, such features may be omitted such that the step shown inblock (4040) is omitted. In the event that such features are included,instrument (10) may provide an audible, visual, and/or tactileindication in the event that the sensing feature(s) detected that theactuation stroke of stapling head assembly (300) was successfullycompleted, as shown in block (4042).

Once stapling head assembly (300) has been successfully actuated, anvil(400) may be advanced distally from stapling head assembly (300) andinstrument (10) may be withdrawn from the patient, as shown in block(4044). After instrument (10) has been withdrawn from the patient, theoperator may remove battery pack (120) from handle assembly (100), asshown in block (4046).

As noted above, the above-described steps of process (4000) are merelyillustrative examples. Instrument (10) may be used in various other waysas will be apparent to those of ordinary skill in the art in view of theteachings herein. In addition, instrument (10) may have various otherfunctionalities as will be apparent to those of ordinary skill in theart in view of the teachings herein.

III. Exemplary Control Circuits for Surgical Stapler

As noted above with reference to block (4032), it may be desirable toensure that the firing mechanism for stapling head assembly (300)completes a full actuation stroke in response to actuation of firingtrigger (150). In other words, it may be desirable to prevent subsequentmanipulation of firing trigger (150) from having any effect on thefiring mechanism completing the actuation stroke of stapling headassembly (300). In some instances, instrument (10) may incorporatemechanical features that ensure completion of a full actuation stroke ofstapling head assembly (300) in response to actuation of firing trigger(150), regardless of subsequent manipulation of firing trigger (150).Examples of such mechanical features are described in U.S. Pub. No.2015/0083774, entitled “Control Features for Motorized Surgical StaplingInstrument,” published Mar. 26, 2015, the disclosure of which isincorporated by reference herein. In addition to or as a alternative tousing such mechanical features, instrument (10) may include electroniccomponents that ensure completion of a full actuation stroke of staplinghead assembly (300) in response to actuation of firing trigger (150),regardless of subsequent manipulation of firing trigger (150). Severalexamples of such electrical features are described in greater detailbelow, while further examples will be apparent to those of ordinaryskill in the art in view of the teachings herein.

A. Exemplary Relay-Based Control Circuit for Surgical Stapler

FIGS. 23A-23F show an exemplary circuit (4100) that may be readilyincorporated into instrument (10). In particular, circuit (4100)includes components that may be incorporated into motor activationmodule (180) and short circuit module (190). Circuit (4100) furtherincludes battery pack (120), motor (160), a battery drain module (4112),and a feedback module (4130).

In the present example, motor activation module (180) includes a switch(4120) and a relay (4122). Switch (4120) is configured to be closed bypaddle (158) of firing trigger (150) when firing trigger (150) ispivoted from the position shown in FIG. 12D to the position shown inFIG. 12E. By way of example only, switch (4120) may comprise a singlepole single throw (SPST) momentary tactile switch. Alternatively, switch(4120) may take any other suitable form. Relay (4122) comprises aconventional polarized double pole double throw (DPDT) relay, such thatrelay (4122) includes a pair of integral switches (4124). Motoractivation module (180) is in communication with motor (160) and batterypack (120) via feedback module (4130).

Short circuit module (190) of the present example comprises a pair ofswitches (4140). Switches (4140) are configured to be actuated by paddle(806) of rocker member (800) when rocker member is pivoted from theposition shown in FIGS. 19A and 20A-20C to the position shown in FIGS.19B and 20D. Short circuit module (190) is in communication with motor(160) and motor activation module (4120) via feedback module (4130).

Battery drain module (4112) of the present example comprises a pair ofresistors and a positive temperature coefficient (PTC) current limitingdevice. By way of example only, battery drain module (4112) may beconstructed and operable in accordance with at least some of theteachings of U.S. Patent App. No. [ATTORNEY DOCKET NO. END7583USNP.0622770], entitled “Surgical Stapler with Ready State Indicator,” filedon even date herewith, the disclosure of which is incorporated byreference herein. Battery drain module (4112) is in communication with aswitch (4110), with battery (120), and with feedback module (4130).

Feedback module (4130) of the present example comprises a pair ofbacklight light emitting diodes (LEDs) (4132) and an indicator LED(4134). Backlight LEDs (4132) are configured and positioned to providebacklight illumination to a display that is provided in window (114). Asnoted above, window (114) is operable to reveal the position ofindicator needle (526) as the operator adjusts the gap distance (d)between opposing surfaces (412, 322) of anvil (400) and stapling headassembly (300). Backlight LEDs (4132) may thus assist in visualizationof the position of indicator needle (526) in window (114). In additionor in the alternative, window (114) may include a backlit display thatis configured and operable in accordance with at least some of theteachings of U.S. Patent App. No. [ATTORNEY DOCKET NO. END7583USNP.0622770], entitled “Surgical Stapler with Ready State Indicator,” filedon even date herewith, the disclosure of which is incorporated byreference herein. In addition or in the alternative, window (114) mayinclude a backlit display that is configured and operable in accordancewith at least some of the teachings of U.S. Patent App. No. [ATTORNEYDOCKET NO. END7584USNP.0622771], entitled “Surgical Stapler with AnvilState Indicator,” filed on even date herewith, the disclosure of whichis incorporated by reference herein. Other suitable displays that may beprovided through window (114) and backlit by LEDs (4132) will beapparent to those of ordinary skill in the art in view of the teachingsherein. It should also be understood that backlight LEDs (4132) aremerely optional and may be omitted if desired.

Indicator LED (4134) is configured to illuminate, change color, orotherwise react to an operational condition associated with instrument(10). For instance, indicator LED (4134) may be configured to providevisual feedback indicating whether anvil (400) is fully coupled withtrocar (330). Indicator LED (4134) may thus be in communication withanvil (400) detection features such as those taught in U.S. Patent App.No. [ATTORNEY DOCKET NO. END7581USNP.0622754], entitled “SurgicalStapler with Anvil Seating Detection,” filed on even date herewith, thedisclosure of which is incorporated by reference herein. In addition orin the alternative, indicator LED (4134) may be configured to providevisual feedback indicating whether stapling head assembly (300) is in aready to fire state. Indicator LED (4134) may thus be in communicationwith anvil (400) features such as those taught in U.S. Patent App. No.[ATTORNEY DOCKET NO. END7583USNP. 0622770], entitled “Surgical Staplerwith Ready State Indicator,” filed on even date herewith, the disclosureof which is incorporated by reference herein. In addition or in thealternative, indicator LED (4134) may be configured to provide visualfeedback indicating whether anvil (400) has been sufficiently advancedaway from stapling head assembly (300) after a firing stapling headassembly (300) has been actuated and before instrument (10) is removedfrom the patient. Indicator LED (4134) may thus be in communication withanvil (400) position detection features such as those taught in U.S.Patent App. No. [ATTORNEY DOCKET NO. END7584USNP.0622771], entitled“Surgical Stapler with Anvil State Indicator,” filed on even dateherewith, the disclosure of which is incorporated by reference herein.In addition or in the alternative, indicator LED (4134) may beconfigured to provide visual feedback indicating a level of stresswithin the firing mechanism for stapling head assembly (300) and/orindicating whether stapling head assembly (300) has been fully actuated.Indicator LED (4134) may thus be in communication with sensingcomponents such as those taught in U.S. Patent App. No. [ATTORNEY DOCKETNO. END7585USNP.0622773], entitled “Surgical Stapler with IncompleteFiring Indicator,” filed on even date herewith, the disclosure of whichis incorporated by reference herein. Still other conditions that may beindicated through indicator LED (4134) will be apparent to those ofordinary skill in the art in view of the teachings herein. It shouldalso be understood that feedback module (4130) may include any suitablenumber of indicator LEDs (4134); or may simply lack an indicator LED(4134) altogether.

As a sequence, FIGS. 23A-23F show the various states of circuit (4100)during operation of instrument (10). In particular, FIG. 23A showscircuit (4100) in a state before battery pack (120) is inserted intohandle assembly (10).

FIG. 23B shows circuit (4100) in a state where battery pack (120) hasbeen inserted into handle assembly (10). The insertion of battery pack(120) into handle assembly (10) has automatically closed switch (4110),such that battery pack (120) is electrically coupled with battery drainmodule (4112). This corresponds with block (4004) from process (4000) ofFIGS. 22A-22B. As noted above, switch (4110) may be closed by insertionof battery pack (120) in accordance with at least some of the teachingsof U.S. Patent App. No. [ATTORNEY DOCKET NO. END7583USNP. 0622770],entitled “Surgical Stapler with Ready State Indicator,” filed on evendate herewith, the disclosure of which is incorporated by referenceherein. It should also be understood that backlight LEDs (4132) mayilluminate in response to insertion of battery pack (120) in handleassembly (100).

FIG. 23C shows circuit (4100) in a state where the operator has actuatedfiring trigger (150), thereby closing switch (4120). This correspondswith block (4030) from process (4000) of FIGS. 22A-22B. Relay (4122) isconfigured to automatically and immediately actuate both switches (4124)in response to closure of switch (4120), as shown in FIG. 23D. Suchactuation of switches (4124) is provided by relay (4122) throughactivation of a magnet in response to closure of switch (4120), as isknown in the art. Closure of switches (4124) will complete a circuitbetween battery (120) and motor (160), thereby causing motor (160) toactuate the firing mechanism of stapling head assembly (300) asdescribed above.

Relay (4122) of the present example is configured such that, onceswitches (4124) are transitioned from the state shown in FIGS. 23A-23Cto the state shown in FIG. 23D, switches (4124) will remain in the stateshown in FIG. 23D regardless of what subsequently happens with switch(4120). In particular, FIG. 23E shows switch (4120) transitioned back tothe open state (e.g., by the operator releasing a grip on firing trigger(150) or intentionally moving trigger (150) back from the position shownin FIG. 12E to the position shown in FIG. 12D, etc.). Despite switch(4120) being transitioned back to the open state as shown in FIG. 23E,switches (4124) remain in the state first shown in FIG. 23D. In otherwords, switches (4124) maintain completion of the circuit betweenbattery (120) and motor (160), thereby ensuring that motor (160) willcomplete actuation of the firing mechanism of stapling head assembly(300) even with switch (4120) transitioned back to the open state. Relay(4122) thus provides a commitment to completion of the actuation strokein accordance with block (4032).

FIG. 23F shows circuit (4000) in a state where paddle (806) of rockermember (800) has changed the state of switches (4140). In this state,switches (4140) provide a short for circuit motor (160). In addition todecoupling motor (160) from battery (120), this short circuiting ofmotor (160) provides a braking effect on motor (160). By way of exampleonly, this effect may be provided in accordance with at least some ofthe teachings of U.S. Pub. No. 2015/0083774, entitled “Control Featuresfor Motorized Surgical Stapling Instrument,” published Mar. 26, 2015,the disclosure of which is incorporated by reference herein. At thisstage of operation, the operator may translate anvil (400) distally torelease tissue from between opposing surfaces (412, 322) of anvil (400)and stapling head assembly (300) and then remove instrument (10) fromthe patient in accordance with block (4044). In the event that theoperator fails to subsequently remove battery pack (120) from handleassembly (100) in accordance with block (4046), battery drain module(4112) will continue to drain power from battery pack (120) until nopower is left in battery pack (120). It should also be understood that,since relay (4122) comprises a conventional polarized double pole doublethrow (DPDT) relay, an operator may not successfully cause motor (160)to operate in reverse simply by reversing the polarity of the voltageapplied to motor (160) via relay (4122).

FIG. 24 shows another exemplary circuit (4200), which is a merelyillustrative variation of circuit (4100). Circuit (4200) of this examplethus also includes components that may be incorporated into motoractivation module (180) and short circuit module (190). Circuit (4200)further includes battery pack (120), motor (160), and a feedback module(4230). While circuit (4200) of this example lacks a battery drainmodule, it should be understood that a battery drain module (similar toa battery drain module (4112) or otherwise configured) may be readilyincorporated into circuit (4200).

Short circuit module (190) of circuit (4200) is substantially identicalto short circuit module (190) of circuit (4100) except that shortcircuit module (190) of circuit (4200) includes just one switch (4240)instead of two switches (4140). Feedback module (4230) of circuit (4200)is substantially identical to feedback module (4130) of circuit (4100).In particular, feedback module (4230) of circuit (4200) includes a pairof backlight light emitting diodes (LEDs) (4232) and an indicator LED(4234). LEDs (4232, 4234) are configured and operable just like LEDs(4132, 4134) of circuit (4100).

Motor activation module (180) of circuit (4200) is substantiallyidentical to motor activation module (180) of circuit (4100). Inparticular, motor activation module (180) of circuit (4200) includes aswitch (4220) and a relay (4222). Switch (4220) is configured to beclosed by paddle (158) of firing trigger (150) when firing trigger (150)is pivoted from the position shown in FIG. 12D to the position shown inFIG. 12E. Relay (4222) comprises a conventional double pole double throw(DPDT) relay, such that relay (4222) includes a pair of integralswitches (4224). As described above with respect to relay (4122), relay(4222) of circuit (4200) provides a commitment to completion of theactuation stroke in accordance with block (4032) of FIGS. 22A-22B. Inparticular, once switch (4120) is actuated by paddle (158) of firingtrigger (150), switches (4224) maintain completion of the circuitbetween battery (120) and motor (160), thereby ensuring that motor (160)will complete actuation of the firing mechanism of stapling headassembly (300) even if switch (4220) is transitioned back to the openstate.

Unlike motor activation module (180) of circuit (4100), motor activationmodule (180) of circuit (4200) further includes a hold-up capacitor(4226). Hold-up capacitor (4226) is applied across the electromechanicalcoil of relay (4222). Hold-up capacitor (4226) is configured to preventmechanical shock from impacting the performance of relay (4222). Forinstance, as noted above, some versions of anvil (400) include abreakable washer within annular recess (418). This washer is broken byknife member (340) when knife member (340) completes a full distal rangeof motion from the position shown in FIG. 21C to the position shown inFIG. 21D. When knife member (340) breaks the washer, this breakage ofthe washer may provide a mechanical shock (e.g., similar to a mechanicalshock encountered when a piece of rigid plastic is broken). Thismechanical shock may be communicated along shaft assembly (200) tocomponents in handle assembly (100). In instances, this mechanical shockmay tend to jar one or both switches (4224) back to the open state,which may disrupt completion of the firing stroke. Even in the presenceof such mechanical shock, hold-up capacitor (4226) may maintainactivation of relay (4222), maintaining power to motor (160) and therebyensuring undisturbed completion of the firing stroke.

B. Exemplary Transistor-Based Control Circuit for Surgical Stapler

FIG. 25 shows another exemplary circuit (4300) that may be readilyincorporated into instrument (10). In particular, circuit (4300)includes components that may be incorporated into motor activationmodule (180) and short circuit module (190). Circuit (4300) comprises afiring switch (4320), a stop switch (4340), a set of bipolar transistors(4322, 4324, 4350, 4352), and an indicator LED (4334). Circuit (4300) isin communication with battery pack (not shown in FIG. 25) via two setsof dual schottky diodes (4360). Diodes (4360) maintain current flow in asingle direction.

Firing switch (4320) is configured to be closed by paddle (158) offiring trigger (150) when firing trigger (150) is pivoted from theposition shown in FIG. 12D to the position shown in FIG. 12E. By way ofexample only, switch (4320) may comprise a single pole single throw(SPST) momentary tactile switch. Alternatively, switch (4320) may takeany other suitable form. Stop switch (4340) is configured to be actuatedby paddle (806) of rocker member (800) when rocker member is pivotedfrom the position shown in FIGS. 19A and 20A-20C to the position shownin FIGS. 19B and 20D.

Latching transistor (4322) is configured to provide a function similarto that provided by relays (4122, 4222) described above. In particular,latching transistor (4322) is configured to cooperate with a drivertransistor (4322) to activate motor (160) in response to closure offiring switch (4320); and to maintain activation of motor (160) throughthe completion of the firing stroke even in the event that firing switch(4320) transitions back to an open state prior to completion of thefiring stroke. In other words, latching transistor (4322) provides acommitment to completion of the actuation stroke in accordance withblock (4032) of FIGS. 22A-22B. Various suitable ways in whichtransistors (4322, 4324) may be constructed and operable will beapparent to those of ordinary skill in the art in view of the teachingsherein. A snubber diode (4370) further provides a current path for motorgenerated voltage. Snubber diode (4370) thus snubs or limits the voltagethat the rest of circuit (4300) might otherwise be exposed to. It shouldbe understood that power interruptions will not cause behavioralanomalies in circuit (4300). For instance, power interruptions may bedue to high current draws such as those caused by a weak battery orelectrical contacts that are not being fully contacted. Suchinterruptions may have a duration that is less than a second, and insome cases milliseconds.

Stop switch (4340) is configured to activate a motor brake transistor(4350) and a motor brake pre-driver transistor (4352) to provide brakingof motor (160) upon completion of the firing stroke as described above.Various suitable ways in which transistors (4350, 4352) may beconstructed and operable will be apparent to those of ordinary skill inthe art in view of the teachings herein.

Indicator LED (4334) is configured to illuminate, change color, orotherwise react to an operational condition associated with instrument(10). For instance, indicator LED (4334) may be configured to providevisual feedback indicating whether anvil (400) is fully coupled withtrocar (330). Indicator LED (4334) may thus be in communication withanvil (400) detection features such as those taught in U.S. Patent App.No. [ATTORNEY DOCKET NO. END7581USNP.0622754], entitled “SurgicalStapler with Anvil Seating Detection,” filed on even date herewith, thedisclosure of which is incorporated by reference herein. In addition orin the alternative, indicator LED (4334) may be configured to providevisual feedback indicating whether stapling head assembly (300) is in aready to fire state. Indicator LED (4334) may thus be in communicationwith anvil (400) features such as those taught in U.S. Patent App. No.[ATTORNEY DOCKET NO. END7583USNP. 0622770], entitled “Surgical Staplerwith Ready State Indicator,” filed on even date herewith, the disclosureof which is incorporated by reference herein. In addition or in thealternative, indicator LED (4334) may be configured to provide visualfeedback indicating whether anvil (400) has been sufficiently advancedaway from stapling head assembly (300) after a firing stapling headassembly (300) has been actuated and before instrument (10) is removedfrom the patient. Indicator LED (4334) may thus be in communication withanvil (400) position detection features such as those taught in U.S.Patent App. No. [ATTORNEY DOCKET NO. END7584USNP.0622771], entitled“Surgical Stapler with Anvil State Indicator,” filed on even dateherewith, the disclosure of which is incorporated by reference herein.In addition or in the alternative, indicator LED (4334) may beconfigured to provide visual feedback indicating a level of stresswithin the firing mechanism for stapling head assembly (300) and/orindicating whether stapling head assembly (300) has been fully actuated.Indicator LED (4334) may thus be in communication with sensingcomponents such as those taught in U.S. Patent App. No. [ATTORNEY DOCKETNO. END7585USNP.0622773], entitled “Surgical Stapler with IncompleteFiring Indicator,” filed on even date herewith, the disclosure of whichis incorporated by reference herein. Still other conditions that may beindicated through indicator LED (4334) will be apparent to those ofordinary skill in the art in view of the teachings herein. It shouldalso be understood that circuit (4300) may include any suitable numberof indicator LEDs (4334); or may simply lack an indicator LED (4334)altogether

C. Exemplary Microprocessor-Based Control Circuit for Surgical Stapler

FIG. 26 shows another exemplary circuit (4400) that may be readilyincorporated into instrument (10). In particular, circuit (4400)includes battery pack (120), motor (160), a firing switch (4420), a stopswitch (4440), and a microprocessor (4450). Firing switch (4420) isconfigured to be closed by paddle (158) of firing trigger (150) whenfiring trigger (150) is pivoted from the position shown in FIG. 12D tothe position shown in FIG. 12E. By way of example only, switch (4420)may comprise a single pole single throw (SPST) momentary tactile switch.Alternatively, switch (4420) may take any other suitable form. Stopswitch (4440) is configured to be actuated by paddle (806) of rockermember (800) when rocker member is pivoted from the position shown inFIGS. 19A and 20A-20C to the position shown in FIGS. 19B and 20D.

Microprocessor (4450) is configured to serve as a central hub for theother components of circuit (4400). In addition, microprocessor (4450)is programmed to activate motor (160) in response to closure of firingswitch (4420); and to maintain activation of motor (160) through thecompletion of the firing stroke even in the event that firing switch(4420) transitions back to an open state prior to completion of thefiring stroke. In other words, microprocessor (4450) provides acommitment to completion of the actuation stroke in accordance withblock (4032) of FIGS. 22A-22B. Microprocessor (4450) is also configuredto provide braking of motor (160) upon completion of the firing strokeas described above. Microprocessor (4450) thus provides a single,comprehensive alternative to relays (4122, 4222) and transistors (4322,4324, 4350, 4352) as described above. Various suitable ways in whichmicroprocessor (4450) may be constructed and operable will be apparentto those of ordinary skill in the art in view of the teachings herein.In some versions, microprocessor (4450) is configured in accordancewith, operable in accordance with, and/or placed in an arrangement withother components in accordance with at least some of the teachings ofU.S. patent application Ser. No. 14/226,142, entitled “SurgicalInstrument Comprising a Sensor System,” filed Mar. 26, 2014, thedisclosure of which is incorporated by reference herein.

IV. Exemplary Combinations

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

EXAMPLE 1

A surgical instrument comprising: (a) a body; (b) a shaft assemblyextending distally from the body; (c) a stapling head assembly locatedat the distal end of the shaft assembly, wherein the stapling headassembly is operable to drive an annular array of staples throughtissue; (d) an anvil, wherein the anvil is configured to cooperate withthe stapling head assembly to deform staples driven through tissue bythe stapling head assembly; (e) a firing assembly, wherein the firingassembly is operable to actuate the stapling head assembly to drive theannular array of staples toward the anvil; (f) a motor, wherein themotor is operable to actuate the firing assembly through an actuationstroke to thereby actuate the stapling head assembly; (g) a user inputfeature, wherein the user input feature is operable transition betweenan actuated state and a non-actuated state; and (h) an electricalcircuit in communication with the user input feature and with the motor,wherein the electrical circuit comprises: (i) a trigger switch, whereinthe trigger switch is configured to transition from an open state to aclosed state in response to the user input feature transitioning fromthe non-actuated state to the actuated state, wherein the electricalcircuit is configured to activate the motor in response to closure ofthe trigger switch, and (ii) an electrical latching feature operable tomaintain activation of the motor to complete the actuation stroke evenif the trigger switch is transitioned back to the open state beforecompletion of the actuation stroke.

EXAMPLE 2

The surgical instrument of Example 1, wherein the electrical latchingfeature comprises a transistor.

EXAMPLE 3

The surgical instrument of Example 1, wherein the electrical latchingfeature comprises a microprocessor.

EXAMPLE 4

The surgical instrument of Example 1, wherein the electrical latchingfeature comprises a relay.

EXAMPLE 5

The surgical instrument of Example 4, wherein the relay comprises adouble pole double throw relay.

EXAMPLE 6

The surgical instrument of any one or more of Examples 4 through 5,wherein the electrical circuit further comprises a hold-up capacitorcoupled with the relay.

EXAMPLE 7

The surgical instrument of any one or more of Examples 1 through 6,wherein the electrical circuit further comprises a short circuit module,wherein the short circuit module is configured to provide a shortcircuit to the motor in response to completion of the actuation stroke.

EXAMPLE 8

The surgical instrument of Example 7, wherein the short circuit modulecomprises a short circuit switch, wherein the short circuit switch isconfigured to transition between a first state and a second state,wherein the short circuit switch is configured to provide the shortcircuit when the short circuit switch is transitioned to the secondstate.

EXAMPLE 9

The surgical instrument of Example 8, further comprising a deactivationmember, wherein the deactivation member is configured to transitionbetween an actuated state and a non-actuated state, wherein thedeactivation member is configured to maintain the non-actuated stateduring the activation stroke, wherein the deactivation member isconfigured to transition from the non-actuated state to the actuatedstate in response to completion of the actuation stroke, wherein thedeactivation member is configured to transition the short circuit switchfrom the first state to the second state in response to the deactivationmember being transitioned to the actuated state.

EXAMPLE 10

The surgical instrument of Example 9, wherein the firing assemblycomprises a movable member configured to engage the deactivation memberupon completion of the firing stroke to thereby transition thedeactivation member from the non-actuated state to the actuated state.

EXAMPLE 11

The surgical instrument of any one or more of Examples 1 through 10,wherein the user input feature comprises a trigger pivotably coupledwith the body, wherein the trigger is pivotable from a first position toa second position to thereby transition from the non-actuated state tothe actuated state.

EXAMPLE 12

The surgical instrument of Example 11, wherein the trigger comprises apaddle, wherein the paddle is configured to engage the trigger switch tothereby transition the trigger switch from the open state to the closedstate in response to pivoting of the trigger from the first position tothe second position

EXAMPLE 13

The surgical instrument of Example 12, wherein the paddle is configuredto disengage the trigger switch in response to pivoting of the triggerfrom the second position to the first position.

EXAMPLE 14

The surgical instrument of any one or more of Examples 1 through 13,wherein the firing assembly comprises a translating member extendingthrough the shaft assembly, wherein the translating member is configuredto translate distally through the shaft assembly during a first portionof the actuation stroke, wherein the translating member is configured totranslate proximally through the shaft assembly during a second portionof the actuation stroke.

EXAMPLE 15

The surgical instrument of Example 14, wherein the stapling headassembly comprises a staple driver and a tissue cutting member, whereinthe translating member is configured to drive the staple driver and thetissue cutting member distally during the first portion of the actuationstroke, wherein the translating member is configured to drive the stapledriver and the tissue cutting member proximally during the secondportion of the actuation stroke.

EXAMPLE 16

The surgical instrument of any one or more of Examples 1 through 15,wherein the electrical circuit further comprises a user feedback featureconfigured to indicate completion of the firing stroke.

EXAMPLE 17

The surgical instrument of Example 16, wherein the user feedback featurecomprises a light emitting diode.

EXAMPLE 18

The surgical instrument of any one or more of Examples 1 through 17,further comprising a battery, wherein the battery is configured toprovide electrical power to the motor via the electrical circuit,wherein the electrical circuit further comprises a battery drain module,wherein the battery drain module is configured to drain power from thebattery after completion of the actuation stroke.

EXAMPLE 19

A surgical instrument comprising: (a) a body; (b) a shaft assemblyextending distally from the body; (c) a stapling head assembly locatedat the distal end of the shaft assembly, wherein the stapling headassembly is operable to drive an annular array of staples throughtissue; (d) an anvil, wherein the anvil is configured to cooperate withthe stapling head assembly to deform staples driven through tissue bythe stapling head assembly; (e) a firing assembly, wherein the firingassembly is operable to actuate the stapling head assembly to drive theannular array of staples toward the anvil; (f) a motor, wherein themotor is operable to actuate the firing assembly through an actuationstroke to thereby actuate the stapling head assembly; (g) a triggerpivotably coupled with the body, wherein the trigger is operable topivot between a first position and a second position; and (h) anelectrical circuit in communication with the user input feature and withthe motor, wherein the electrical circuit comprises: (i) a triggerswitch, wherein the trigger is configured to engage the trigger switchto thereby transition the trigger switch from an open state to a closedstate in response to pivoting of the trigger from the first position tothe second position, wherein the trigger is configured to disengage thetrigger switch in response to pivoting of the trigger from the secondposition to the first position, wherein the electrical circuit isconfigured to activate the motor in response to closure of the triggerswitch, and (ii) a control feature operable to maintain activation ofthe motor to complete the actuation stroke even if the trigger switch istransitioned back to the open state before completion of the actuationstroke.

EXAMPLE 20

A method of operating a surgical stapling instrument, wherein theinstrument comprises: (a) a stapling head assembly, wherein the staplinghead assembly is operable to drive an annular array of staples throughtissue; (b) an anvil, wherein the anvil is configured to cooperate withthe stapling head assembly to deform staples driven through tissue bythe stapling head assembly; (c) a firing assembly, wherein the firingassembly is operable to actuate the stapling head assembly to drive theannular array of staples toward the anvil; (d) a motor, wherein themotor is operable to actuate the firing assembly through an actuationstroke to thereby actuate the stapling head assembly; and (e) a userinput feature, wherein the user input feature is operable transitionbetween an actuated state and a non-actuated state; wherein the methodcomprises: (a) actuating the user input feature to thereby transitionthe user input feature from the non-actuated state to the actuatedstate, wherein the act of actuating the user input feature comprisesclosing a trigger switch; (b) activating the motor in response toclosure of the trigger switch, wherein activation of the motor initiatesthe actuation stroke; (c) opening the trigger switch; (d) maintainingactivation of the motor to complete the actuation stroke after thetrigger switch is opened; and (e) de-activating the motor uponcompletion of the actuation stroke.

V. Miscellaneous

It should also be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

At least some of the teachings herein may be readily combined with oneor more teachings of U.S. Pat. No. 7,794,475, entitled “Surgical StaplesHaving Compressible or Crushable Members for Securing Tissue Therein andStapling Instruments for Deploying the Same,” issued Sep. 14, 2010, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2014/0151429, entitled “Trans-Oral Circular Anvil Introduction Systemwith Dilation Feature,” published Jun. 5, 2014, the disclosure of whichis incorporated by reference herein; U.S. Pub. No. 2014/0144968,entitled “Surgical Staple with Integral Pledget for Tip Deflection,”published May 29, 2014, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2014/0158747, entitled “Surgical Staplerwith Varying Staple Widths along Different Circumferences,” publishedJun. 12, 2014, the disclosure of which is incorporated by referenceherein; U.S. Pub. No. 2014/0144969, entitled “Pivoting Anvil forSurgical Circular Stapler,” published May 29, 2014, the disclosure ofwhich is incorporated by reference herein; U.S. Pub. No. 2014/0151430,entitled “Circular Anvil Introduction System with Alignment Feature,”published Jun. 5, 2014, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2014/0166717, entitled “Circular Staplerwith Selectable Motorized and Manual Control, Including a Control Ring,”published Jun. 19, 2014, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2014/0166728, entitled “Motor DrivenRotary Input Circular Stapler with Modular End Effector,” published Jun.19, 2014, the disclosure of which is incorporated by reference herein;and/or U.S. Pub. No. 2014/0166718, entitled “Motor Driven Rotary InputCircular Stapler with Lockable Flexible Shaft,” published Jun. 19, 2014,the disclosure of which is incorporated by reference herein. Varioussuitable ways in which such teachings may be combined will be apparentto those of ordinary skill in the art.

While the examples herein have been provided in the context of acircular stapling instrument, it should be understood that the variousteachings herein may be readily applied to various other kinds ofsurgical instruments. By way of example only, the various teachingsherein may be readily applied to linear stapling devices (e.g.,endocutters). For instance, various teachings herein may be readilycombined with various teachings of U.S. Pub. No. 2012/0239012, entitled“Motor-Driven Surgical Cutting Instrument with Electric ActuatorDirectional Control Assembly,” published Sep. 20, 2012, the disclosureof which is incorporated by reference herein, and/or U.S. Pub. No.2010/0264193, entitled “Surgical Stapling Instrument with AnArticulatable End Effector,” published Oct. 21, 2010, the disclosure ofwhich is incorporated by reference herein, as will be apparent to thoseof ordinary skill in the art. As another merely illustrative example,the various teachings herein may be readily applied to a motorizedelectrosurgical device. For instance, various teachings herein may bereadily combined with various teachings of U.S. Pub. No. 2012/0116379,entitled “Motor Driven Electrosurgical Device with Mechanical andElectrical Feedback,” published May 10, 2012, the disclosure of which isincorporated by reference herein, as will be apparent to those ofordinary skill in the art. Other suitable kinds of instruments in whichthe teachings herein may be applied, and various ways in which theteachings herein may be applied to such instruments, will be apparent tothose of ordinary skill in the art.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions of the devices described above may have application inconventional medical treatments and procedures conducted by a medicalprofessional, as well as application in robotic-assisted medicaltreatments and procedures. By way of example only, various teachingsherein may be readily incorporated into a robotic surgical system suchas the DAVINCI™ system by Intuitive Surgical, Inc., of Sunnyvale, Calif.

Versions described above may be designed to be disposed of after asingle use, or they can be designed to be used multiple times. Versionsmay, in either or both cases, be reconditioned for reuse after at leastone use. Reconditioning may include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, someversions of the device may be disassembled, and any number of theparticular pieces or parts of the device may be selectively replaced orremoved in any combination. Upon cleaning and/or replacement ofparticular parts, some versions of the device may be reassembled forsubsequent use either at a reconditioning facility, or by a userimmediately prior to a procedure. Those skilled in the art willappreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein may be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device may then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation may kill bacteria on thedevice and in the container. The sterilized device may then be stored inthe sterile container for later use. A device may also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

I/We claim:
 1. A surgical instrument comprising: (a) a body; (b) a shaft assembly extending distally from the body; (c) a stapling head assembly located at the distal end of the shaft assembly, wherein the stapling head assembly is operable to drive an annular array of staples through tissue; (d) an anvil, wherein the anvil is configured to cooperate with the stapling head assembly to deform staples driven through tissue by the stapling head assembly; (e) a firing assembly, wherein the firing assembly is operable to actuate the stapling head assembly to drive the annular array of staples toward the anvil; a motor, wherein the motor is operable to actuate the firing assembly through an actuation stroke to thereby actuate the stapling head assembly; (g) a user input feature, wherein the user input feature is operable transition between an actuated state and a non-actuated state; and (h) an electrical circuit in communication with the user input feature and with the motor, wherein the electrical circuit comprises: (i) a trigger switch, wherein the trigger switch is configured to transition from an open state to a closed state in response to the user input feature transitioning from the non-actuated state to the actuated state, wherein the electrical circuit is configured to activate the motor in response to closure of the trigger switch, and (ii) an electrical latching feature operable to maintain activation of the motor to complete the actuation stroke even if the trigger switch is transitioned back to the open state before completion of the actuation stroke.
 2. The surgical instrument of claim 1, wherein the electrical latching feature comprises a transistor.
 3. The surgical instrument of claim 1, wherein the electrical latching feature comprises a microprocessor.
 4. The surgical instrument of claim 1, wherein the electrical latching feature comprises a relay.
 5. The surgical instrument of claim 4, wherein the relay comprises a double pole double throw relay.
 6. The surgical instrument of claim 4, wherein the electrical circuit further comprises a hold-up capacitor coupled with the relay.
 7. The surgical instrument of claim 1, wherein the electrical circuit further comprises a short circuit module, wherein the short circuit module is configured to provide a short circuit to the motor in response to completion of the actuation stroke.
 8. The surgical instrument of claim 7, wherein the short circuit module comprises a short circuit switch, wherein the short circuit switch is configured to transition between a first state and a second state, wherein the short circuit switch is configured to provide the short circuit when the short circuit switch is transitioned to the second state.
 9. The surgical instrument of claim 8, further comprising a deactivation member, wherein the deactivation member is configured to transition between an actuated state and a non-actuated state, wherein the deactivation member is configured to maintain the non-actuated state during the activation stroke, wherein the deactivation member is configured to transition from the non-actuated state to the actuated state in response to completion of the actuation stroke, wherein the deactivation member is configured to transition the short circuit switch from the first state to the second state in response to the deactivation member being transitioned to the actuated state.
 10. The surgical instrument of claim 9, wherein the firing assembly comprises a movable member configured to engage the deactivation member upon completion of the firing stroke to thereby transition the deactivation member from the non-actuated state to the actuated state.
 11. The surgical instrument of claim 1, wherein the user input feature comprises a trigger pivotably coupled with the body, wherein the trigger is pivotable from a first position to a second position to thereby transition from the non-actuated state to the actuated state.
 12. The surgical instrument of claim 11, wherein the trigger comprises a paddle, wherein the paddle is configured to engage the trigger switch to thereby transition the trigger switch from the open state to the closed state in response to pivoting of the trigger from the first position to the second position
 13. The surgical instrument of claim 12, wherein the paddle is configured to disengage the trigger switch in response to pivoting of the trigger from the second position to the first position.
 14. The surgical instrument of claim 1, wherein the firing assembly comprises a translating member extending through the shaft assembly, wherein the translating member is configured to translate distally through the shaft assembly during a first portion of the actuation stroke, wherein the translating member is configured to translate proximally through the shaft assembly during a second portion of the actuation stroke.
 15. The surgical instrument of claim 14, wherein the stapling head assembly comprises a staple driver and a tissue cutting member, wherein the translating member is configured to drive the staple driver and the tissue cutting member distally during the first portion of the actuation stroke, wherein the translating member is configured to drive the staple driver and the tissue cutting member proximally during the second portion of the actuation stroke.
 16. The surgical instrument of claim 1, wherein the electrical circuit further comprises a user feedback feature configured to indicate completion of the firing stroke.
 17. The surgical instrument of claim 16, wherein the user feedback feature comprises a light emitting diode.
 18. The surgical instrument of claim 1, further comprising a battery, wherein the battery is configured to provide electrical power to the motor via the electrical circuit, wherein the electrical circuit further comprises a battery drain module, wherein the battery drain module is configured to drain power from the battery after completion of the actuation stroke.
 19. A surgical instrument comprising: (a) a body; (b) a shaft assembly extending distally from the body; (c) a stapling head assembly located at the distal end of the shaft assembly, wherein the stapling head assembly is operable to drive an annular array of staples through tissue; (d) an anvil, wherein the anvil is configured to cooperate with the stapling head assembly to deform staples driven through tissue by the stapling head assembly; (e) a firing assembly, wherein the firing assembly is operable to actuate the stapling head assembly to drive the annular array of staples toward the anvil; (f) a motor, wherein the motor is operable to actuate the firing assembly through an actuation stroke to thereby actuate the stapling head assembly; (g) a trigger pivotably coupled with the body, wherein the trigger is operable to pivot between a first position and a second position; and (h) an electrical circuit in communication with the user input feature and with the motor, wherein the electrical circuit comprises: (i) a trigger switch, wherein the trigger is configured to engage the trigger switch to thereby transition the trigger switch from an open state to a closed state in response to pivoting of the trigger from the first position to the second position, wherein the trigger is configured to disengage the trigger switch in response to pivoting of the trigger from the second position to the first position, wherein the electrical circuit is configured to activate the motor in response to closure of the trigger switch, and (ii) a control feature operable to maintain activation of the motor to complete the actuation stroke even if the trigger switch is transitioned back to the open state before completion of the actuation stroke.
 20. A method of operating a surgical stapling instrument, wherein the instrument comprises: (a) a stapling head assembly, wherein the stapling head assembly is operable to drive an annular array of staples through tissue; (b) an anvil, wherein the anvil is configured to cooperate with the stapling head assembly to deform staples driven through tissue by the stapling head assembly; (c) a firing assembly, wherein the firing assembly is operable to actuate the stapling head assembly to drive the annular array of staples toward the anvil; (d) a motor, wherein the motor is operable to actuate the firing assembly through an actuation stroke to thereby actuate the stapling head assembly; and (e) a user input feature, wherein the user input feature is operable transition between an actuated state and a non-actuated state; wherein the method comprises: (a) actuating the user input feature to thereby transition the user input feature from the non-actuated state to the actuated state, wherein the act of actuating the user input feature comprises closing a trigger switch; (b) activating the motor in response to closure of the trigger switch, wherein activation of the motor initiates the actuation stroke; (c) opening the trigger switch; (d) maintaining activation of the motor to complete the actuation stroke after the trigger switch is opened; and (e) de-activating the motor upon completion of the actuation stroke. 